code:
import { Alias } from '../nodes/Alias.js';
import { isEmptyPath, collectionFromPath } from '../nodes/Collection.js';
import { NODE_TYPE, DOC, isNode, isCollection, isScalar } from '../nodes/identity.js';
import { Pair } from '../nodes/Pair.js';
import { toJS } from '../nodes/toJS.js';
import { Schema } from '../schema/Schema.js';
import { stringifyDocument } from '../stringify/stringifyDocument.js';
import { anchorNames, findNewAnchor, createNodeAnchors } from './anchors.js';
import { applyReviver } from './applyReviver.js';
import { createNode } from './createNode.js';
import { Directives } from './directives.js';

class Document {
    constructor(value, replacer, options) {
        /** A comment before this Document */
        this.commentBefore = null;
        /** A comment immediately after this Document */
        this.comment = null;
        /** Errors encountered during parsing. */
        this.errors = [];
        /** Warnings encountered during parsing. */
        this.warnings = [];
        Object.defineProperty(this, NODE_TYPE, { value: DOC });
        let _replacer = null;
        if (typeof replacer === 'function' || Array.isArray(replacer)) {
            _replacer = replacer;
        }
        else if (options === undefined && replacer) {
            options = replacer;
            replacer = undefined;
        }
        const opt = Object.assign({
            intAsBigInt: false,
            keepSourceTokens: false,
            logLevel: 'warn',
            prettyErrors: true,
            strict: true,
            uniqueKeys: true,
            version: '1.2'
        }, options);
        this.options = opt;
        let { version } = opt;
        if (options?._directives) {
            this.directives = options._directives.atDocument();
            if (this.directives.yaml.explicit)
                version = this.directives.yaml.version;
        }
        else
            this.directives = new Directives({ version });
        this.setSchema(version, options);
        // @ts-expect-error We can't really know that this matches Contents.
        this.contents =
            value === undefined ? null : this.createNode(value, _replacer, options);
    }
    /**
     * Create a deep copy of this Document and its contents.
     *
     * Custom Node values that inherit from `Object` still refer to their original instances.
     */
    clone() {
        const copy = Object.create(Document.prototype, {
            [NODE_TYPE]: { value: DOC }
        });
        copy.commentBefore = this.commentBefore;
        copy.comment = this.comment;
        copy.errors = this.errors.slice();
        copy.warnings = this.warnings.slice();
        copy.options = Object.assign({}, this.options);
        if (this.directives)
            copy.directives = this.directives.clone();
        copy.schema = this.schema.clone();
        // @ts-expect-error We can't really know that this matches Contents.
        copy.contents = isNode(this.contents)
            ? this.contents.clone(copy.schema)
            : this.contents;
        if (this.range)
            copy.range = this.range.slice();
        return copy;
    }
    /** Adds a value to the document. */
    add(value) {
        if (assertCollection(this.contents))
            this.contents.add(value);
    }
    /** Adds a value to the document. */
    addIn(path, value) {
        if (assertCollection(this.contents))
            this.contents.addIn(path, value);
    }
    /**
     * Create a new `Alias` node, ensuring that the target `node` has the required anchor.
     *
     * If `node` already has an anchor, `name` is ignored.
     * Otherwise, the `node.anchor` value will be set to `name`,
     * or if an anchor with that name is already present in the document,
     * `name` will be used as a prefix for a new unique anchor.
     * If `name` is undefined, the generated anchor will use 'a' as a prefix.
     */
    createAlias(node, name) {
        if (!node.anchor) {
            const prev = anchorNames(this);
            node.anchor =
                // eslint-disable-next-line @typescript-eslint/prefer-nullish-coalescing
                !name || prev.has(name) ? findNewAnchor(name || 'a', prev) : name;
        }
        return new Alias(node.anchor);
    }
    createNode(value, replacer, options) {
        let _replacer = undefined;
        if (typeof replacer === 'function') {
            value = replacer.call({ '': value }, '', value);
            _replacer = replacer;
        }
        else if (Array.isArray(replacer)) {
            const keyToStr = (v) => typeof v === 'number' || v instanceof String || v instanceof Number;
            const asStr = replacer.filter(keyToStr).map(String);
            if (asStr.length > 0)
                replacer = replacer.concat(asStr);
            _replacer = replacer;
        }
        else if (options === undefined && replacer) {
            options = replacer;
            replacer = undefined;
        }
        const { aliasDuplicateObjects, anchorPrefix, flow, keepUndefined, onTagObj, tag } = options ?? {};
        const { onAnchor, setAnchors, sourceObjects } = createNodeAnchors(this,
        // eslint-disable-next-line @typescript-eslint/prefer-nullish-coalescing
        anchorPrefix || 'a');
        const ctx = {
            aliasDuplicateObjects: aliasDuplicateObjects ?? true,
            keepUndefined: keepUndefined ?? false,
            onAnchor,
            onTagObj,
            replacer: _replacer,
            schema: this.schema,
            sourceObjects
        };
        const node = createNode(value, tag, ctx);
        if (flow && isCollection(node))
            node.flow = true;
        setAnchors();
        return node;
    }
    /**
     * Convert a key and a value into a `Pair` using the current schema,
     * recursively wrapping all values as `Scalar` or `Collection` nodes.
     */
    createPair(key, value, options = {}) {
        const k = this.createNode(key, null, options);
        const v = this.createNode(value, null, options);
        return new Pair(k, v);
    }
    /**
     * Removes a value from the document.
     * @returns `true` if the item was found and removed.
     */
    delete(key) {
        return assertCollection(this.contents) ? this.contents.delete(key) : false;
    }
    /**
     * Removes a value from the document.
     * @returns `true` if the item was found and removed.
     */
    deleteIn(path) {
        if (isEmptyPath(path)) {
            if (this.contents == null)
                return false;
            // @ts-expect-error Presumed impossible if Strict extends false
            this.contents = null;
            return true;
        }
        return assertCollection(this.contents)
            ? this.contents.deleteIn(path)
            : false;
    }
    /**
     * Returns item at `key`, or `undefined` if not found. By default unwraps
     * scalar values from their surrounding node; to disable set `keepScalar` to
     * `true` (collections are always returned intact).
     */
    get(key, keepScalar) {
        return isCollection(this.contents)
            ? this.contents.get(key, keepScalar)
            : undefined;
    }
    /**
     * Returns item at `path`, or `undefined` if not found. By default unwraps
     * scalar values from their surrounding node; to disable set `keepScalar` to
     * `true` (collections are always returned intact).
     */
    getIn(path, keepScalar) {
        if (isEmptyPath(path))
            return !keepScalar && isScalar(this.contents)
                ? this.contents.value
                : this.contents;
        return isCollection(this.contents)
            ? this.contents.getIn(path, keepScalar)
            : undefined;
    }
    /**
     * Checks if the document includes a value with the key `key`.
     */
    has(key) {
        return isCollection(this.contents) ? this.contents.has(key) : false;
    }
    /**
     * Checks if the document includes a value at `path`.
     */
    hasIn(path) {
        if (isEmptyPath(path))
            return this.contents !== undefined;
        return isCollection(this.contents) ? this.contents.hasIn(path) : false;
    }
    /**
     * Sets a value in this document. For `!!set`, `value` needs to be a
     * boolean to add/remove the item from the set.
     */
    set(key, value) {
        if (this.contents == null) {
            // @ts-expect-error We can't really know that this matches Contents.
            this.contents = collectionFromPath(this.schema, [key], value);
        }
        else if (assertCollection(this.contents)) {
            this.contents.set(key, value);
        }
    }
    /**
     * Sets a value in this document. For `!!set`, `value` needs to be a
     * boolean to add/remove the item from the set.
     */
    setIn(path, value) {
        if (isEmptyPath(path)) {
            // @ts-expect-error We can't really know that this matches Contents.
            this.contents = value;
        }
        else if (this.contents == null) {
            // @ts-expect-error We can't really know that this matches Contents.
            this.contents = collectionFromPath(this.schema, Array.from(path), value);
        }
        else if (assertCollection(this.contents)) {
            this.contents.setIn(path, value);
        }
    }
    /**
     * Change the YAML version and schema used by the document.
     * A `null` version disables support for directives, explicit tags, anchors, and aliases.
     * It also requires the `schema` option to be given as a `Schema` instance value.
     *
     * Overrides all previously set schema options.
     */
    setSchema(version, options = {}) {
        if (typeof version === 'number')
            version = String(version);
        let opt;
        switch (version) {
            case '1.1':
                if (this.directives)
                    this.directives.yaml.version = '1.1';
                else
                    this.directives = new Directives({ version: '1.1' });
                opt = { merge: true, resolveKnownTags: false, schema: 'yaml-1.1' };
                break;
            case '1.2':
            case 'next':
                if (this.directives)
                    this.directives.yaml.version = version;
                else
                    this.directives = new Directives({ version });
                opt = { merge: false, resolveKnownTags: true, schema: 'core' };
                break;
            case null:
                if (this.directives)
                    delete this.directives;
                opt = null;
                break;
            default: {
                const sv = JSON.stringify(version);
                throw new Error(`Expected '1.1', '1.2' or null as first argument, but found: ${sv}`);
            }
        }
        // Not using `instanceof Schema` to allow for duck typing
        if (options.schema instanceof Object)
            this.schema = options.schema;
        else if (opt)
            this.schema = new Schema(Object.assign(opt, options));
        else
            throw new Error(`With a null YAML version, the { schema: Schema } option is required`);
    }
    // json & jsonArg are only used from toJSON()
    toJS({ json, jsonArg, mapAsMap, maxAliasCount, onAnchor, reviver } = {}) {
        const ctx = {
            anchors: new Map(),
            doc: this,
            keep: !json,
            mapAsMap: mapAsMap === true,
            mapKeyWarned: false,
            maxAliasCount: typeof maxAliasCount === 'number' ? maxAliasCount : 100
        };
        const res = toJS(this.contents, jsonArg ?? '', ctx);
        if (typeof onAnchor === 'function')
            for (const { count, res } of ctx.anchors.values())
                onAnchor(res, count);
        return typeof reviver === 'function'
            ? applyReviver(reviver, { '': res }, '', res)
            : res;
    }
    /**
     * A JSON representation of the document `contents`.
     *
     * @param jsonArg Used by `JSON.stringify` to indicate the array index or
     *   property name.
     */
    toJSON(jsonArg, onAnchor) {
        return this.toJS({ json: true, jsonArg, mapAsMap: false, onAnchor });
    }
    /** A YAML representation of the document. */
    toString(options = {}) {
        if (this.errors.length > 0)
            throw new Error('Document with errors cannot be stringified');
        if ('indent' in options &&
            (!Number.isInteger(options.indent) || Number(options.indent) <= 0)) {
            const s = JSON.stringify(options.indent);
            throw new Error(`"indent" option must be a positive integer, not ${s}`);
        }
        return stringifyDocument(this, options);
    }
}
function assertCollection(contents) {
    if (isCollection(contents))
        return true;
    throw new Error('Expected a YAML collection as document contents');
}

export { Document };


code:
import { isScalar, isCollection } from '../nodes/identity.js';
import { visit } from '../visit.js';

/**
 * Verify that the input string is a valid anchor.
 *
 * Will throw on errors.
 */
function anchorIsValid(anchor) {
    if (/[\x00-\x19\s,[\]{}]/.test(anchor)) {
        const sa = JSON.stringify(anchor);
        const msg = `Anchor must not contain whitespace or control characters: ${sa}`;
        throw new Error(msg);
    }
    return true;
}
function anchorNames(root) {
    const anchors = new Set();
    visit(root, {
        Value(_key, node) {
            if (node.anchor)
                anchors.add(node.anchor);
        }
    });
    return anchors;
}
/** Find a new anchor name with the given `prefix` and a one-indexed suffix. */
function findNewAnchor(prefix, exclude) {
    for (let i = 1; true; ++i) {
        const name = `${prefix}${i}`;
        if (!exclude.has(name))
            return name;
    }
}
function createNodeAnchors(doc, prefix) {
    const aliasObjects = [];
    const sourceObjects = new Map();
    let prevAnchors = null;
    return {
        onAnchor: (source) => {
            aliasObjects.push(source);
            if (!prevAnchors)
                prevAnchors = anchorNames(doc);
            const anchor = findNewAnchor(prefix, prevAnchors);
            prevAnchors.add(anchor);
            return anchor;
        },
        /**
         * With circular references, the source node is only resolved after all
         * of its child nodes are. This is why anchors are set only after all of
         * the nodes have been created.
         */
        setAnchors: () => {
            for (const source of aliasObjects) {
                const ref = sourceObjects.get(source);
                if (typeof ref === 'object' &&
                    ref.anchor &&
                    (isScalar(ref.node) || isCollection(ref.node))) {
                    ref.node.anchor = ref.anchor;
                }
                else {
                    const error = new Error('Failed to resolve repeated object (this should not happen)');
                    error.source = source;
                    throw error;
                }
            }
        },
        sourceObjects
    };
}

export { anchorIsValid, anchorNames, createNodeAnchors, findNewAnchor };

license: mit


code:
/**
 * Applies the JSON.parse reviver algorithm as defined in the ECMA-262 spec,
 * in section 24.5.1.1 "Runtime Semantics: InternalizeJSONProperty" of the
 * 2021 edition: https://tc39.es/ecma262/#sec-json.parse
 *
 * Includes extensions for handling Map and Set objects.
 */
function applyReviver(reviver, obj, key, val) {
    if (val && typeof val === 'object') {
        if (Array.isArray(val)) {
            for (let i = 0, len = val.length; i < len; ++i) {
                const v0 = val[i];
                const v1 = applyReviver(reviver, val, String(i), v0);
                // eslint-disable-next-line @typescript-eslint/no-array-delete
                if (v1 === undefined)
                    delete val[i];
                else if (v1 !== v0)
                    val[i] = v1;
            }
        }
        else if (val instanceof Map) {
            for (const k of Array.from(val.keys())) {
                const v0 = val.get(k);
                const v1 = applyReviver(reviver, val, k, v0);
                if (v1 === undefined)
                    val.delete(k);
                else if (v1 !== v0)
                    val.set(k, v1);
            }
        }
        else if (val instanceof Set) {
            for (const v0 of Array.from(val)) {
                const v1 = applyReviver(reviver, val, v0, v0);
                if (v1 === undefined)
                    val.delete(v0);
                else if (v1 !== v0) {
                    val.delete(v0);
                    val.add(v1);
                }
            }
        }
        else {
            for (const [k, v0] of Object.entries(val)) {
                const v1 = applyReviver(reviver, val, k, v0);
                if (v1 === undefined)
                    delete val[k];
                else if (v1 !== v0)
                    val[k] = v1;
            }
        }
    }
    return reviver.call(obj, key, val);
}

export { applyReviver };


code:
import { Alias } from '../nodes/Alias.js';
import { isNode, isPair, MAP, SEQ, isDocument } from '../nodes/identity.js';
import { Scalar } from '../nodes/Scalar.js';

const defaultTagPrefix = 'tag:yaml.org,2002:';
function findTagObject(value, tagName, tags) {
    if (tagName) {
        const match = tags.filter(t => t.tag === tagName);
        const tagObj = match.find(t => !t.format) ?? match[0];
        if (!tagObj)
            throw new Error(`Tag ${tagName} not found`);
        return tagObj;
    }
    return tags.find(t => t.identify?.(value) && !t.format);
}
function createNode(value, tagName, ctx) {
    if (isDocument(value))
        value = value.contents;
    if (isNode(value))
        return value;
    if (isPair(value)) {
        const map = ctx.schema[MAP].createNode?.(ctx.schema, null, ctx);
        map.items.push(value);
        return map;
    }
    if (value instanceof String ||
        value instanceof Number ||
        value instanceof Boolean ||
        (typeof BigInt !== 'undefined' && value instanceof BigInt) // not supported everywhere
    ) {
        // https://tc39.es/ecma262/#sec-serializejsonproperty
        value = value.valueOf();
    }
    const { aliasDuplicateObjects, onAnchor, onTagObj, schema, sourceObjects } = ctx;
    // Detect duplicate references to the same object & use Alias nodes for all
    // after first. The `ref` wrapper allows for circular references to resolve.
    let ref = undefined;
    if (aliasDuplicateObjects && value && typeof value === 'object') {
        ref = sourceObjects.get(value);
        if (ref) {
            if (!ref.anchor)
                ref.anchor = onAnchor(value);
            return new Alias(ref.anchor);
        }
        else {
            ref = { anchor: null, node: null };
            sourceObjects.set(value, ref);
        }
    }
    if (tagName?.startsWith('!!'))
        tagName = defaultTagPrefix + tagName.slice(2);
    let tagObj = findTagObject(value, tagName, schema.tags);
    if (!tagObj) {
        if (value && typeof value.toJSON === 'function') {
            // eslint-disable-next-line @typescript-eslint/no-unsafe-call
            value = value.toJSON();
        }
        if (!value || typeof value !== 'object') {
            const node = new Scalar(value);
            if (ref)
                ref.node = node;
            return node;
        }
        tagObj =
            value instanceof Map
                ? schema[MAP]
                : Symbol.iterator in Object(value)
                    ? schema[SEQ]
                    : schema[MAP];
    }
    if (onTagObj) {
        onTagObj(tagObj);
        delete ctx.onTagObj;
    }
    const node = tagObj?.createNode
        ? tagObj.createNode(ctx.schema, value, ctx)
        : typeof tagObj?.nodeClass?.from === 'function'
            ? tagObj.nodeClass.from(ctx.schema, value, ctx)
            : new Scalar(value);
    if (tagName)
        node.tag = tagName;
    else if (!tagObj.default)
        node.tag = tagObj.tag;
    if (ref)
        ref.node = node;
    return node;
}

export { createNode };


code:
import { isNode } from '../nodes/identity.js';
import { visit } from '../visit.js';

const escapeChars = {
    '!': '%21',
    ',': '%2C',
    '[': '%5B',
    ']': '%5D',
    '{': '%7B',
    '}': '%7D'
};
const escapeTagName = (tn) => tn.replace(/[!,[\]{}]/g, ch => escapeChars[ch]);
class Directives {
    constructor(yaml, tags) {
        /**
         * The directives-end/doc-start marker `---`. If `null`, a marker may still be
         * included in the document's stringified representation.
         */
        this.docStart = null;
        /** The doc-end marker `...`.  */
        this.docEnd = false;
        this.yaml = Object.assign({}, Directives.defaultYaml, yaml);
        this.tags = Object.assign({}, Directives.defaultTags, tags);
    }
    clone() {
        const copy = new Directives(this.yaml, this.tags);
        copy.docStart = this.docStart;
        return copy;
    }
    /**
     * During parsing, get a Directives instance for the current document and
     * update the stream state according to the current version's spec.
     */
    atDocument() {
        const res = new Directives(this.yaml, this.tags);
        switch (this.yaml.version) {
            case '1.1':
                this.atNextDocument = true;
                break;
            case '1.2':
                this.atNextDocument = false;
                this.yaml = {
                    explicit: Directives.defaultYaml.explicit,
                    version: '1.2'
                };
                this.tags = Object.assign({}, Directives.defaultTags);
                break;
        }
        return res;
    }
    /**
     * @param onError - May be called even if the action was successful
     * @returns `true` on success
     */
    add(line, onError) {
        if (this.atNextDocument) {
            this.yaml = { explicit: Directives.defaultYaml.explicit, version: '1.1' };
            this.tags = Object.assign({}, Directives.defaultTags);
            this.atNextDocument = false;
        }
        const parts = line.trim().split(/[ \t]+/);
        const name = parts.shift();
        switch (name) {
            case '%TAG': {
                if (parts.length !== 2) {
                    onError(0, '%TAG directive should contain exactly two parts');
                    if (parts.length < 2)
                        return false;
                }
                const [handle, prefix] = parts;
                this.tags[handle] = prefix;
                return true;
            }
            case '%YAML': {
                this.yaml.explicit = true;
                if (parts.length !== 1) {
                    onError(0, '%YAML directive should contain exactly one part');
                    return false;
                }
                const [version] = parts;
                if (version === '1.1' || version === '1.2') {
                    this.yaml.version = version;
                    return true;
                }
                else {
                    const isValid = /^\d+\.\d+$/.test(version);
                    onError(6, `Unsupported YAML version ${version}`, isValid);
                    return false;
                }
            }
            default:
                onError(0, `Unknown directive ${name}`, true);
                return false;
        }
    }
    /**
     * Resolves a tag, matching handles to those defined in %TAG directives.
     *
     * @returns Resolved tag, which may also be the non-specific tag `'!'` or a
     *   `'!local'` tag, or `null` if unresolvable.
     */
    tagName(source, onError) {
        if (source === '!')
            return '!'; // non-specific tag
        if (source[0] !== '!') {
            onError(`Not a valid tag: ${source}`);
            return null;
        }
        if (source[1] === '<') {
            const verbatim = source.slice(2, -1);
            if (verbatim === '!' || verbatim === '!!') {
                onError(`Verbatim tags aren't resolved, so ${source} is invalid.`);
                return null;
            }
            if (source[source.length - 1] !== '>')
                onError('Verbatim tags must end with a >');
            return verbatim;
        }
        const [, handle, suffix] = source.match(/^(.*!)([^!]*)$/s);
        if (!suffix)
            onError(`The ${source} tag has no suffix`);
        const prefix = this.tags[handle];
        if (prefix) {
            try {
                return prefix + decodeURIComponent(suffix);
            }
            catch (error) {
                onError(String(error));
                return null;
            }
        }
        if (handle === '!')
            return source; // local tag
        onError(`Could not resolve tag: ${source}`);
        return null;
    }
    /**
     * Given a fully resolved tag, returns its printable string form,
     * taking into account current tag prefixes and defaults.
     */
    tagString(tag) {
        for (const [handle, prefix] of Object.entries(this.tags)) {
            if (tag.startsWith(prefix))
                return handle + escapeTagName(tag.substring(prefix.length));
        }
        return tag[0] === '!' ? tag : `!<${tag}>`;
    }
    toString(doc) {
        const lines = this.yaml.explicit
            ? [`%YAML ${this.yaml.version || '1.2'}`]
            : [];
        const tagEntries = Object.entries(this.tags);
        let tagNames;
        if (doc && tagEntries.length > 0 && isNode(doc.contents)) {
            const tags = {};
            visit(doc.contents, (_key, node) => {
                if (isNode(node) && node.tag)
                    tags[node.tag] = true;
            });
            tagNames = Object.keys(tags);
        }
        else
            tagNames = [];
        for (const [handle, prefix] of tagEntries) {
            if (handle === '!!' && prefix === 'tag:yaml.org,2002:')
                continue;
            if (!doc || tagNames.some(tn => tn.startsWith(prefix)))
                lines.push(`%TAG ${handle} ${prefix}`);
        }
        return lines.join('\n');
    }
}
Directives.defaultYaml = { explicit: false, version: '1.2' };
Directives.defaultTags = { '!!': 'tag:yaml.org,2002:' };

export { Directives };


code:
class YAMLError extends Error {
    constructor(name, pos, code, message) {
        super();
        this.name = name;
        this.code = code;
        this.message = message;
        this.pos = pos;
    }
}
class YAMLParseError extends YAMLError {
    constructor(pos, code, message) {
        super('YAMLParseError', pos, code, message);
    }
}
class YAMLWarning extends YAMLError {
    constructor(pos, code, message) {
        super('YAMLWarning', pos, code, message);
    }
}
const prettifyError = (src, lc) => (error) => {
    if (error.pos[0] === -1)
        return;
    error.linePos = error.pos.map(pos => lc.linePos(pos));
    const { line, col } = error.linePos[0];
    error.message += ` at line ${line}, column ${col}`;
    let ci = col - 1;
    let lineStr = src
        .substring(lc.lineStarts[line - 1], lc.lineStarts[line])
        .replace(/[\n\r]+$/, '');
    // Trim to max 80 chars, keeping col position near the middle
    if (ci >= 60 && lineStr.length > 80) {
        const trimStart = Math.min(ci - 39, lineStr.length - 79);
        lineStr = '…' + lineStr.substring(trimStart);
        ci -= trimStart - 1;
    }
    if (lineStr.length > 80)
        lineStr = lineStr.substring(0, 79) + '…';
    // Include previous line in context if pointing at line start
    if (line > 1 && /^ *$/.test(lineStr.substring(0, ci))) {
        // Regexp won't match if start is trimmed
        let prev = src.substring(lc.lineStarts[line - 2], lc.lineStarts[line - 1]);
        if (prev.length > 80)
            prev = prev.substring(0, 79) + '…\n';
        lineStr = prev + lineStr;
    }
    if (/[^ ]/.test(lineStr)) {
        let count = 1;
        const end = error.linePos[1];
        if (end && end.line === line && end.col > col) {
            count = Math.max(1, Math.min(end.col - col, 80 - ci));
        }
        const pointer = ' '.repeat(ci) + '^'.repeat(count);
        error.message += `:\n\n${lineStr}\n${pointer}\n`;
    }
};

export { YAMLError, YAMLParseError, YAMLWarning, prettifyError };


code:
export { Composer } from './compose/composer.js';
export { Document } from './doc/Document.js';
export { Schema } from './schema/Schema.js';
export { YAMLError, YAMLParseError, YAMLWarning } from './errors.js';
export { Alias } from './nodes/Alias.js';
export { isAlias, isCollection, isDocument, isMap, isNode, isPair, isScalar, isSeq } from './nodes/identity.js';
export { Pair } from './nodes/Pair.js';
export { Scalar } from './nodes/Scalar.js';
export { YAMLMap } from './nodes/YAMLMap.js';
export { YAMLSeq } from './nodes/YAMLSeq.js';
import * as cst from './parse/cst.js';
export { cst as CST };
export { Lexer } from './parse/lexer.js';
export { LineCounter } from './parse/line-counter.js';
export { Parser } from './parse/parser.js';
export { parse, parseAllDocuments, parseDocument, stringify } from './public-api.js';
export { visit, visitAsync } from './visit.js';


code:
function debug(logLevel, ...messages) {
    if (logLevel === 'debug')
        console.log(...messages);
}
function warn(logLevel, warning) {
    if (logLevel === 'debug' || logLevel === 'warn') {
        if (typeof process !== 'undefined' && process.emitWarning)
            process.emitWarning(warning);
        else
            console.warn(warning);
    }
}

export { debug, warn };


code:
import { anchorIsValid } from '../doc/anchors.js';
import { visit } from '../visit.js';
import { ALIAS, isAlias, isCollection, isPair } from './identity.js';
import { NodeBase } from './Node.js';
import { toJS } from './toJS.js';

class Alias extends NodeBase {
    constructor(source) {
        super(ALIAS);
        this.source = source;
        Object.defineProperty(this, 'tag', {
            set() {
                throw new Error('Alias nodes cannot have tags');
            }
        });
    }
    /**
     * Resolve the value of this alias within `doc`, finding the last
     * instance of the `source` anchor before this node.
     */
    resolve(doc) {
        let found = undefined;
        visit(doc, {
            Node: (_key, node) => {
                if (node === this)
                    return visit.BREAK;
                if (node.anchor === this.source)
                    found = node;
            }
        });
        return found;
    }
    toJSON(_arg, ctx) {
        if (!ctx)
            return { source: this.source };
        const { anchors, doc, maxAliasCount } = ctx;
        const source = this.resolve(doc);
        if (!source) {
            const msg = `Unresolved alias (the anchor must be set before the alias): ${this.source}`;
            throw new ReferenceError(msg);
        }
        let data = anchors.get(source);
        if (!data) {
            // Resolve anchors for Node.prototype.toJS()
            toJS(source, null, ctx);
            data = anchors.get(source);
        }
        /* istanbul ignore if */
        if (!data || data.res === undefined) {
            const msg = 'This should not happen: Alias anchor was not resolved?';
            throw new ReferenceError(msg);
        }
        if (maxAliasCount >= 0) {
            data.count += 1;
            if (data.aliasCount === 0)
                data.aliasCount = getAliasCount(doc, source, anchors);
            if (data.count * data.aliasCount > maxAliasCount) {
                const msg = 'Excessive alias count indicates a resource exhaustion attack';
                throw new ReferenceError(msg);
            }
        }
        return data.res;
    }
    toString(ctx, _onComment, _onChompKeep) {
        const src = `*${this.source}`;
        if (ctx) {
            anchorIsValid(this.source);
            if (ctx.options.verifyAliasOrder && !ctx.anchors.has(this.source)) {
                const msg = `Unresolved alias (the anchor must be set before the alias): ${this.source}`;
                throw new Error(msg);
            }
            if (ctx.implicitKey)
                return `${src} `;
        }
        return src;
    }
}
function getAliasCount(doc, node, anchors) {
    if (isAlias(node)) {
        const source = node.resolve(doc);
        const anchor = anchors && source && anchors.get(source);
        return anchor ? anchor.count * anchor.aliasCount : 0;
    }
    else if (isCollection(node)) {
        let count = 0;
        for (const item of node.items) {
            const c = getAliasCount(doc, item, anchors);
            if (c > count)
                count = c;
        }
        return count;
    }
    else if (isPair(node)) {
        const kc = getAliasCount(doc, node.key, anchors);
        const vc = getAliasCount(doc, node.value, anchors);
        return Math.max(kc, vc);
    }
    return 1;
}

export { Alias };


code:
import { createNode } from '../doc/createNode.js';
import { isNode, isPair, isCollection, isScalar } from './identity.js';
import { NodeBase } from './Node.js';

function collectionFromPath(schema, path, value) {
    let v = value;
    for (let i = path.length - 1; i >= 0; --i) {
        const k = path[i];
        if (typeof k === 'number' && Number.isInteger(k) && k >= 0) {
            const a = [];
            a[k] = v;
            v = a;
        }
        else {
            v = new Map([[k, v]]);
        }
    }
    return createNode(v, undefined, {
        aliasDuplicateObjects: false,
        keepUndefined: false,
        onAnchor: () => {
            throw new Error('This should not happen, please report a bug.');
        },
        schema,
        sourceObjects: new Map()
    });
}
// Type guard is intentionally a little wrong so as to be more useful,
// as it does not cover untypable empty non-string iterables (e.g. []).
const isEmptyPath = (path) => path == null ||
    (typeof path === 'object' && !!path[Symbol.iterator]().next().done);
class Collection extends NodeBase {
    constructor(type, schema) {
        super(type);
        Object.defineProperty(this, 'schema', {
            value: schema,
            configurable: true,
            enumerable: false,
            writable: true
        });
    }
    /**
     * Create a copy of this collection.
     *
     * @param schema - If defined, overwrites the original's schema
     */
    clone(schema) {
        const copy = Object.create(Object.getPrototypeOf(this), Object.getOwnPropertyDescriptors(this));
        if (schema)
            copy.schema = schema;
        copy.items = copy.items.map(it => isNode(it) || isPair(it) ? it.clone(schema) : it);
        if (this.range)
            copy.range = this.range.slice();
        return copy;
    }
    /**
     * Adds a value to the collection. For `!!map` and `!!omap` the value must
     * be a Pair instance or a `{ key, value }` object, which may not have a key
     * that already exists in the map.
     */
    addIn(path, value) {
        if (isEmptyPath(path))
            this.add(value);
        else {
            const [key, ...rest] = path;
            const node = this.get(key, true);
            if (isCollection(node))
                node.addIn(rest, value);
            else if (node === undefined && this.schema)
                this.set(key, collectionFromPath(this.schema, rest, value));
            else
                throw new Error(`Expected YAML collection at ${key}. Remaining path: ${rest}`);
        }
    }
    /**
     * Removes a value from the collection.
     * @returns `true` if the item was found and removed.
     */
    deleteIn(path) {
        const [key, ...rest] = path;
        if (rest.length === 0)
            return this.delete(key);
        const node = this.get(key, true);
        if (isCollection(node))
            return node.deleteIn(rest);
        else
            throw new Error(`Expected YAML collection at ${key}. Remaining path: ${rest}`);
    }
    /**
     * Returns item at `key`, or `undefined` if not found. By default unwraps
     * scalar values from their surrounding node; to disable set `keepScalar` to
     * `true` (collections are always returned intact).
     */
    getIn(path, keepScalar) {
        const [key, ...rest] = path;
        const node = this.get(key, true);
        if (rest.length === 0)
            return !keepScalar && isScalar(node) ? node.value : node;
        else
            return isCollection(node) ? node.getIn(rest, keepScalar) : undefined;
    }
    hasAllNullValues(allowScalar) {
        return this.items.every(node => {
            if (!isPair(node))
                return false;
            const n = node.value;
            return (n == null ||
                (allowScalar &&
                    isScalar(n) &&
                    n.value == null &&
                    !n.commentBefore &&
                    !n.comment &&
                    !n.tag));
        });
    }
    /**
     * Checks if the collection includes a value with the key `key`.
     */
    hasIn(path) {
        const [key, ...rest] = path;
        if (rest.length === 0)
            return this.has(key);
        const node = this.get(key, true);
        return isCollection(node) ? node.hasIn(rest) : false;
    }
    /**
     * Sets a value in this collection. For `!!set`, `value` needs to be a
     * boolean to add/remove the item from the set.
     */
    setIn(path, value) {
        const [key, ...rest] = path;
        if (rest.length === 0) {
            this.set(key, value);
        }
        else {
            const node = this.get(key, true);
            if (isCollection(node))
                node.setIn(rest, value);
            else if (node === undefined && this.schema)
                this.set(key, collectionFromPath(this.schema, rest, value));
            else
                throw new Error(`Expected YAML collection at ${key}. Remaining path: ${rest}`);
        }
    }
}

export { Collection, collectionFromPath, isEmptyPath };


code:
import { applyReviver } from '../doc/applyReviver.js';
import { NODE_TYPE, isDocument } from './identity.js';
import { toJS } from './toJS.js';

class NodeBase {
    constructor(type) {
        Object.defineProperty(this, NODE_TYPE, { value: type });
    }
    /** Create a copy of this node.  */
    clone() {
        const copy = Object.create(Object.getPrototypeOf(this), Object.getOwnPropertyDescriptors(this));
        if (this.range)
            copy.range = this.range.slice();
        return copy;
    }
    /** A plain JavaScript representation of this node. */
    toJS(doc, { mapAsMap, maxAliasCount, onAnchor, reviver } = {}) {
        if (!isDocument(doc))
            throw new TypeError('A document argument is required');
        const ctx = {
            anchors: new Map(),
            doc,
            keep: true,
            mapAsMap: mapAsMap === true,
            mapKeyWarned: false,
            maxAliasCount: typeof maxAliasCount === 'number' ? maxAliasCount : 100
        };
        const res = toJS(this, '', ctx);
        if (typeof onAnchor === 'function')
            for (const { count, res } of ctx.anchors.values())
                onAnchor(res, count);
        return typeof reviver === 'function'
            ? applyReviver(reviver, { '': res }, '', res)
            : res;
    }
}

export { NodeBase };


code:
import { createNode } from '../doc/createNode.js';
import { stringifyPair } from '../stringify/stringifyPair.js';
import { addPairToJSMap } from './addPairToJSMap.js';
import { NODE_TYPE, PAIR, isNode } from './identity.js';

function createPair(key, value, ctx) {
    const k = createNode(key, undefined, ctx);
    const v = createNode(value, undefined, ctx);
    return new Pair(k, v);
}
class Pair {
    constructor(key, value = null) {
        Object.defineProperty(this, NODE_TYPE, { value: PAIR });
        this.key = key;
        this.value = value;
    }
    clone(schema) {
        let { key, value } = this;
        if (isNode(key))
            key = key.clone(schema);
        if (isNode(value))
            value = value.clone(schema);
        return new Pair(key, value);
    }
    toJSON(_, ctx) {
        const pair = ctx?.mapAsMap ? new Map() : {};
        return addPairToJSMap(ctx, pair, this);
    }
    toString(ctx, onComment, onChompKeep) {
        return ctx?.doc
            ? stringifyPair(this, ctx, onComment, onChompKeep)
            : JSON.stringify(this);
    }
}

export { Pair, createPair };


code:
import { SCALAR } from './identity.js';
import { NodeBase } from './Node.js';
import { toJS } from './toJS.js';

const isScalarValue = (value) => !value || (typeof value !== 'function' && typeof value !== 'object');
class Scalar extends NodeBase {
    constructor(value) {
        super(SCALAR);
        this.value = value;
    }
    toJSON(arg, ctx) {
        return ctx?.keep ? this.value : toJS(this.value, arg, ctx);
    }
    toString() {
        return String(this.value);
    }
}
Scalar.BLOCK_FOLDED = 'BLOCK_FOLDED';
Scalar.BLOCK_LITERAL = 'BLOCK_LITERAL';
Scalar.PLAIN = 'PLAIN';
Scalar.QUOTE_DOUBLE = 'QUOTE_DOUBLE';
Scalar.QUOTE_SINGLE = 'QUOTE_SINGLE';

export { Scalar, isScalarValue };


code:
import { stringifyCollection } from '../stringify/stringifyCollection.js';
import { addPairToJSMap } from './addPairToJSMap.js';
import { Collection } from './Collection.js';
import { isPair, isScalar, MAP } from './identity.js';
import { Pair, createPair } from './Pair.js';
import { isScalarValue } from './Scalar.js';

function findPair(items, key) {
    const k = isScalar(key) ? key.value : key;
    for (const it of items) {
        if (isPair(it)) {
            if (it.key === key || it.key === k)
                return it;
            if (isScalar(it.key) && it.key.value === k)
                return it;
        }
    }
    return undefined;
}
class YAMLMap extends Collection {
    static get tagName() {
        return 'tag:yaml.org,2002:map';
    }
    constructor(schema) {
        super(MAP, schema);
        this.items = [];
    }
    /**
     * A generic collection parsing method that can be extended
     * to other node classes that inherit from YAMLMap
     */
    static from(schema, obj, ctx) {
        const { keepUndefined, replacer } = ctx;
        const map = new this(schema);
        const add = (key, value) => {
            if (typeof replacer === 'function')
                value = replacer.call(obj, key, value);
            else if (Array.isArray(replacer) && !replacer.includes(key))
                return;
            if (value !== undefined || keepUndefined)
                map.items.push(createPair(key, value, ctx));
        };
        if (obj instanceof Map) {
            for (const [key, value] of obj)
                add(key, value);
        }
        else if (obj && typeof obj === 'object') {
            for (const key of Object.keys(obj))
                add(key, obj[key]);
        }
        if (typeof schema.sortMapEntries === 'function') {
            map.items.sort(schema.sortMapEntries);
        }
        return map;
    }
    /**
     * Adds a value to the collection.
     *
     * @param overwrite - If not set `true`, using a key that is already in the
     *   collection will throw. Otherwise, overwrites the previous value.
     */
    add(pair, overwrite) {
        let _pair;
        if (isPair(pair))
            _pair = pair;
        else if (!pair || typeof pair !== 'object' || !('key' in pair)) {
            // In TypeScript, this never happens.
            _pair = new Pair(pair, pair?.value);
        }
        else
            _pair = new Pair(pair.key, pair.value);
        const prev = findPair(this.items, _pair.key);
        const sortEntries = this.schema?.sortMapEntries;
        if (prev) {
            if (!overwrite)
                throw new Error(`Key ${_pair.key} already set`);
            // For scalars, keep the old node & its comments and anchors
            if (isScalar(prev.value) && isScalarValue(_pair.value))
                prev.value.value = _pair.value;
            else
                prev.value = _pair.value;
        }
        else if (sortEntries) {
            const i = this.items.findIndex(item => sortEntries(_pair, item) < 0);
            if (i === -1)
                this.items.push(_pair);
            else
                this.items.splice(i, 0, _pair);
        }
        else {
            this.items.push(_pair);
        }
    }
    delete(key) {
        const it = findPair(this.items, key);
        if (!it)
            return false;
        const del = this.items.splice(this.items.indexOf(it), 1);
        return del.length > 0;
    }
    get(key, keepScalar) {
        const it = findPair(this.items, key);
        const node = it?.value;
        return (!keepScalar && isScalar(node) ? node.value : node) ?? undefined;
    }
    has(key) {
        return !!findPair(this.items, key);
    }
    set(key, value) {
        this.add(new Pair(key, value), true);
    }
    /**
     * @param ctx - Conversion context, originally set in Document#toJS()
     * @param {Class} Type - If set, forces the returned collection type
     * @returns Instance of Type, Map, or Object
     */
    toJSON(_, ctx, Type) {
        const map = Type ? new Type() : ctx?.mapAsMap ? new Map() : {};
        if (ctx?.onCreate)
            ctx.onCreate(map);
        for (const item of this.items)
            addPairToJSMap(ctx, map, item);
        return map;
    }
    toString(ctx, onComment, onChompKeep) {
        if (!ctx)
            return JSON.stringify(this);
        for (const item of this.items) {
            if (!isPair(item))
                throw new Error(`Map items must all be pairs; found ${JSON.stringify(item)} instead`);
        }
        if (!ctx.allNullValues && this.hasAllNullValues(false))
            ctx = Object.assign({}, ctx, { allNullValues: true });
        return stringifyCollection(this, ctx, {
            blockItemPrefix: '',
            flowChars: { start: '{', end: '}' },
            itemIndent: ctx.indent || '',
            onChompKeep,
            onComment
        });
    }
}

export { YAMLMap, findPair };


code:
import { createNode } from '../doc/createNode.js';
import { stringifyCollection } from '../stringify/stringifyCollection.js';
import { Collection } from './Collection.js';
import { SEQ, isScalar } from './identity.js';
import { isScalarValue } from './Scalar.js';
import { toJS } from './toJS.js';

class YAMLSeq extends Collection {
    static get tagName() {
        return 'tag:yaml.org,2002:seq';
    }
    constructor(schema) {
        super(SEQ, schema);
        this.items = [];
    }
    add(value) {
        this.items.push(value);
    }
    /**
     * Removes a value from the collection.
     *
     * `key` must contain a representation of an integer for this to succeed.
     * It may be wrapped in a `Scalar`.
     *
     * @returns `true` if the item was found and removed.
     */
    delete(key) {
        const idx = asItemIndex(key);
        if (typeof idx !== 'number')
            return false;
        const del = this.items.splice(idx, 1);
        return del.length > 0;
    }
    get(key, keepScalar) {
        const idx = asItemIndex(key);
        if (typeof idx !== 'number')
            return undefined;
        const it = this.items[idx];
        return !keepScalar && isScalar(it) ? it.value : it;
    }
    /**
     * Checks if the collection includes a value with the key `key`.
     *
     * `key` must contain a representation of an integer for this to succeed.
     * It may be wrapped in a `Scalar`.
     */
    has(key) {
        const idx = asItemIndex(key);
        return typeof idx === 'number' && idx < this.items.length;
    }
    /**
     * Sets a value in this collection. For `!!set`, `value` needs to be a
     * boolean to add/remove the item from the set.
     *
     * If `key` does not contain a representation of an integer, this will throw.
     * It may be wrapped in a `Scalar`.
     */
    set(key, value) {
        const idx = asItemIndex(key);
        if (typeof idx !== 'number')
            throw new Error(`Expected a valid index, not ${key}.`);
        const prev = this.items[idx];
        if (isScalar(prev) && isScalarValue(value))
            prev.value = value;
        else
            this.items[idx] = value;
    }
    toJSON(_, ctx) {
        const seq = [];
        if (ctx?.onCreate)
            ctx.onCreate(seq);
        let i = 0;
        for (const item of this.items)
            seq.push(toJS(item, String(i++), ctx));
        return seq;
    }
    toString(ctx, onComment, onChompKeep) {
        if (!ctx)
            return JSON.stringify(this);
        return stringifyCollection(this, ctx, {
            blockItemPrefix: '- ',
            flowChars: { start: '[', end: ']' },
            itemIndent: (ctx.indent || '') + '  ',
            onChompKeep,
            onComment
        });
    }
    static from(schema, obj, ctx) {
        const { replacer } = ctx;
        const seq = new this(schema);
        if (obj && Symbol.iterator in Object(obj)) {
            let i = 0;
            for (let it of obj) {
                if (typeof replacer === 'function') {
                    const key = obj instanceof Set ? it : String(i++);
                    it = replacer.call(obj, key, it);
                }
                seq.items.push(createNode(it, undefined, ctx));
            }
        }
        return seq;
    }
}
function asItemIndex(key) {
    let idx = isScalar(key) ? key.value : key;
    if (idx && typeof idx === 'string')
        idx = Number(idx);
    return typeof idx === 'number' && Number.isInteger(idx) && idx >= 0
        ? idx
        : null;
}

export { YAMLSeq };


code:
import { warn } from '../log.js';
import { createStringifyContext } from '../stringify/stringify.js';
import { isAlias, isSeq, isScalar, isMap, isNode } from './identity.js';
import { Scalar } from './Scalar.js';
import { toJS } from './toJS.js';

const MERGE_KEY = '<<';
function addPairToJSMap(ctx, map, { key, value }) {
    if (ctx?.doc.schema.merge && isMergeKey(key)) {
        value = isAlias(value) ? value.resolve(ctx.doc) : value;
        if (isSeq(value))
            for (const it of value.items)
                mergeToJSMap(ctx, map, it);
        else if (Array.isArray(value))
            for (const it of value)
                mergeToJSMap(ctx, map, it);
        else
            mergeToJSMap(ctx, map, value);
    }
    else {
        const jsKey = toJS(key, '', ctx);
        if (map instanceof Map) {
            map.set(jsKey, toJS(value, jsKey, ctx));
        }
        else if (map instanceof Set) {
            map.add(jsKey);
        }
        else {
            const stringKey = stringifyKey(key, jsKey, ctx);
            const jsValue = toJS(value, stringKey, ctx);
            if (stringKey in map)
                Object.defineProperty(map, stringKey, {
                    value: jsValue,
                    writable: true,
                    enumerable: true,
                    configurable: true
                });
            else
                map[stringKey] = jsValue;
        }
    }
    return map;
}
const isMergeKey = (key) => key === MERGE_KEY ||
    (isScalar(key) &&
        key.value === MERGE_KEY &&
        (!key.type || key.type === Scalar.PLAIN));
// If the value associated with a merge key is a single mapping node, each of
// its key/value pairs is inserted into the current mapping, unless the key
// already exists in it. If the value associated with the merge key is a
// sequence, then this sequence is expected to contain mapping nodes and each
// of these nodes is merged in turn according to its order in the sequence.
// Keys in mapping nodes earlier in the sequence override keys specified in
// later mapping nodes. -- http://yaml.org/type/merge.html
function mergeToJSMap(ctx, map, value) {
    const source = ctx && isAlias(value) ? value.resolve(ctx.doc) : value;
    if (!isMap(source))
        throw new Error('Merge sources must be maps or map aliases');
    const srcMap = source.toJSON(null, ctx, Map);
    for (const [key, value] of srcMap) {
        if (map instanceof Map) {
            if (!map.has(key))
                map.set(key, value);
        }
        else if (map instanceof Set) {
            map.add(key);
        }
        else if (!Object.prototype.hasOwnProperty.call(map, key)) {
            Object.defineProperty(map, key, {
                value,
                writable: true,
                enumerable: true,
                configurable: true
            });
        }
    }
    return map;
}
function stringifyKey(key, jsKey, ctx) {
    if (jsKey === null)
        return '';
    if (typeof jsKey !== 'object')
        return String(jsKey);
    if (isNode(key) && ctx?.doc) {
        const strCtx = createStringifyContext(ctx.doc, {});
        strCtx.anchors = new Set();
        for (const node of ctx.anchors.keys())
            strCtx.anchors.add(node.anchor);
        strCtx.inFlow = true;
        strCtx.inStringifyKey = true;
        const strKey = key.toString(strCtx);
        if (!ctx.mapKeyWarned) {
            let jsonStr = JSON.stringify(strKey);
            if (jsonStr.length > 40)
                jsonStr = jsonStr.substring(0, 36) + '..."';
            warn(ctx.doc.options.logLevel, `Keys with collection values will be stringified due to JS Object restrictions: ${jsonStr}. Set mapAsMap: true to use object keys.`);
            ctx.mapKeyWarned = true;
        }
        return strKey;
    }
    return JSON.stringify(jsKey);
}

export { addPairToJSMap };


code:
const ALIAS = Symbol.for('yaml.alias');
const DOC = Symbol.for('yaml.document');
const MAP = Symbol.for('yaml.map');
const PAIR = Symbol.for('yaml.pair');
const SCALAR = Symbol.for('yaml.scalar');
const SEQ = Symbol.for('yaml.seq');
const NODE_TYPE = Symbol.for('yaml.node.type');
const isAlias = (node) => !!node && typeof node === 'object' && node[NODE_TYPE] === ALIAS;
const isDocument = (node) => !!node && typeof node === 'object' && node[NODE_TYPE] === DOC;
const isMap = (node) => !!node && typeof node === 'object' && node[NODE_TYPE] === MAP;
const isPair = (node) => !!node && typeof node === 'object' && node[NODE_TYPE] === PAIR;
const isScalar = (node) => !!node && typeof node === 'object' && node[NODE_TYPE] === SCALAR;
const isSeq = (node) => !!node && typeof node === 'object' && node[NODE_TYPE] === SEQ;
function isCollection(node) {
    if (node && typeof node === 'object')
        switch (node[NODE_TYPE]) {
            case MAP:
            case SEQ:
                return true;
        }
    return false;
}
function isNode(node) {
    if (node && typeof node === 'object')
        switch (node[NODE_TYPE]) {
            case ALIAS:
            case MAP:
            case SCALAR:
            case SEQ:
                return true;
        }
    return false;
}
const hasAnchor = (node) => (isScalar(node) || isCollection(node)) && !!node.anchor;

export { ALIAS, DOC, MAP, NODE_TYPE, PAIR, SCALAR, SEQ, hasAnchor, isAlias, isCollection, isDocument, isMap, isNode, isPair, isScalar, isSeq };


code:
import { hasAnchor } from './identity.js';

/**
 * Recursively convert any node or its contents to native JavaScript
 *
 * @param value - The input value
 * @param arg - If `value` defines a `toJSON()` method, use this
 *   as its first argument
 * @param ctx - Conversion context, originally set in Document#toJS(). If
 *   `{ keep: true }` is not set, output should be suitable for JSON
 *   stringification.
 */
function toJS(value, arg, ctx) {
    // eslint-disable-next-line @typescript-eslint/no-unsafe-return
    if (Array.isArray(value))
        return value.map((v, i) => toJS(v, String(i), ctx));
    if (value && typeof value.toJSON === 'function') {
        // eslint-disable-next-line @typescript-eslint/no-unsafe-call
        if (!ctx || !hasAnchor(value))
            return value.toJSON(arg, ctx);
        const data = { aliasCount: 0, count: 1, res: undefined };
        ctx.anchors.set(value, data);
        ctx.onCreate = res => {
            data.res = res;
            delete ctx.onCreate;
        };
        const res = value.toJSON(arg, ctx);
        if (ctx.onCreate)
            ctx.onCreate(res);
        return res;
    }
    if (typeof value === 'bigint' && !ctx?.keep)
        return Number(value);
    return value;
}

export { toJS };


code:
import { resolveBlockScalar } from '../compose/resolve-block-scalar.js';
import { resolveFlowScalar } from '../compose/resolve-flow-scalar.js';
import { YAMLParseError } from '../errors.js';
import { stringifyString } from '../stringify/stringifyString.js';

function resolveAsScalar(token, strict = true, onError) {
    if (token) {
        const _onError = (pos, code, message) => {
            const offset = typeof pos === 'number' ? pos : Array.isArray(pos) ? pos[0] : pos.offset;
            if (onError)
                onError(offset, code, message);
            else
                throw new YAMLParseError([offset, offset + 1], code, message);
        };
        switch (token.type) {
            case 'scalar':
            case 'single-quoted-scalar':
            case 'double-quoted-scalar':
                return resolveFlowScalar(token, strict, _onError);
            case 'block-scalar':
                return resolveBlockScalar({ options: { strict } }, token, _onError);
        }
    }
    return null;
}
/**
 * Create a new scalar token with `value`
 *
 * Values that represent an actual string but may be parsed as a different type should use a `type` other than `'PLAIN'`,
 * as this function does not support any schema operations and won't check for such conflicts.
 *
 * @param value The string representation of the value, which will have its content properly indented.
 * @param context.end Comments and whitespace after the end of the value, or after the block scalar header. If undefined, a newline will be added.
 * @param context.implicitKey Being within an implicit key may affect the resolved type of the token's value.
 * @param context.indent The indent level of the token.
 * @param context.inFlow Is this scalar within a flow collection? This may affect the resolved type of the token's value.
 * @param context.offset The offset position of the token.
 * @param context.type The preferred type of the scalar token. If undefined, the previous type of the `token` will be used, defaulting to `'PLAIN'`.
 */
function createScalarToken(value, context) {
    const { implicitKey = false, indent, inFlow = false, offset = -1, type = 'PLAIN' } = context;
    const source = stringifyString({ type, value }, {
        implicitKey,
        indent: indent > 0 ? ' '.repeat(indent) : '',
        inFlow,
        options: { blockQuote: true, lineWidth: -1 }
    });
    const end = context.end ?? [
        { type: 'newline', offset: -1, indent, source: '\n' }
    ];
    switch (source[0]) {
        case '|':
        case '>': {
            const he = source.indexOf('\n');
            const head = source.substring(0, he);
            const body = source.substring(he + 1) + '\n';
            const props = [
                { type: 'block-scalar-header', offset, indent, source: head }
            ];
            if (!addEndtoBlockProps(props, end))
                props.push({ type: 'newline', offset: -1, indent, source: '\n' });
            return { type: 'block-scalar', offset, indent, props, source: body };
        }
        case '"':
            return { type: 'double-quoted-scalar', offset, indent, source, end };
        case "'":
            return { type: 'single-quoted-scalar', offset, indent, source, end };
        default:
            return { type: 'scalar', offset, indent, source, end };
    }
}
/**
 * Set the value of `token` to the given string `value`, overwriting any previous contents and type that it may have.
 *
 * Best efforts are made to retain any comments previously associated with the `token`,
 * though all contents within a collection's `items` will be overwritten.
 *
 * Values that represent an actual string but may be parsed as a different type should use a `type` other than `'PLAIN'`,
 * as this function does not support any schema operations and won't check for such conflicts.
 *
 * @param token Any token. If it does not include an `indent` value, the value will be stringified as if it were an implicit key.
 * @param value The string representation of the value, which will have its content properly indented.
 * @param context.afterKey In most cases, values after a key should have an additional level of indentation.
 * @param context.implicitKey Being within an implicit key may affect the resolved type of the token's value.
 * @param context.inFlow Being within a flow collection may affect the resolved type of the token's value.
 * @param context.type The preferred type of the scalar token. If undefined, the previous type of the `token` will be used, defaulting to `'PLAIN'`.
 */
function setScalarValue(token, value, context = {}) {
    let { afterKey = false, implicitKey = false, inFlow = false, type } = context;
    let indent = 'indent' in token ? token.indent : null;
    if (afterKey && typeof indent === 'number')
        indent += 2;
    if (!type)
        switch (token.type) {
            case 'single-quoted-scalar':
                type = 'QUOTE_SINGLE';
                break;
            case 'double-quoted-scalar':
                type = 'QUOTE_DOUBLE';
                break;
            case 'block-scalar': {
                const header = token.props[0];
                if (header.type !== 'block-scalar-header')
                    throw new Error('Invalid block scalar header');
                type = header.source[0] === '>' ? 'BLOCK_FOLDED' : 'BLOCK_LITERAL';
                break;
            }
            default:
                type = 'PLAIN';
        }
    const source = stringifyString({ type, value }, {
        implicitKey: implicitKey || indent === null,
        indent: indent !== null && indent > 0 ? ' '.repeat(indent) : '',
        inFlow,
        options: { blockQuote: true, lineWidth: -1 }
    });
    switch (source[0]) {
        case '|':
        case '>':
            setBlockScalarValue(token, source);
            break;
        case '"':
            setFlowScalarValue(token, source, 'double-quoted-scalar');
            break;
        case "'":
            setFlowScalarValue(token, source, 'single-quoted-scalar');
            break;
        default:
            setFlowScalarValue(token, source, 'scalar');
    }
}
function setBlockScalarValue(token, source) {
    const he = source.indexOf('\n');
    const head = source.substring(0, he);
    const body = source.substring(he + 1) + '\n';
    if (token.type === 'block-scalar') {
        const header = token.props[0];
        if (header.type !== 'block-scalar-header')
            throw new Error('Invalid block scalar header');
        header.source = head;
        token.source = body;
    }
    else {
        const { offset } = token;
        const indent = 'indent' in token ? token.indent : -1;
        const props = [
            { type: 'block-scalar-header', offset, indent, source: head }
        ];
        if (!addEndtoBlockProps(props, 'end' in token ? token.end : undefined))
            props.push({ type: 'newline', offset: -1, indent, source: '\n' });
        for (const key of Object.keys(token))
            if (key !== 'type' && key !== 'offset')
                delete token[key];
        Object.assign(token, { type: 'block-scalar', indent, props, source: body });
    }
}
/** @returns `true` if last token is a newline */
function addEndtoBlockProps(props, end) {
    if (end)
        for (const st of end)
            switch (st.type) {
                case 'space':
                case 'comment':
                    props.push(st);
                    break;
                case 'newline':
                    props.push(st);
                    return true;
            }
    return false;
}
function setFlowScalarValue(token, source, type) {
    switch (token.type) {
        case 'scalar':
        case 'double-quoted-scalar':
        case 'single-quoted-scalar':
            token.type = type;
            token.source = source;
            break;
        case 'block-scalar': {
            const end = token.props.slice(1);
            let oa = source.length;
            if (token.props[0].type === 'block-scalar-header')
                oa -= token.props[0].source.length;
            for (const tok of end)
                tok.offset += oa;
            delete token.props;
            Object.assign(token, { type, source, end });
            break;
        }
        case 'block-map':
        case 'block-seq': {
            const offset = token.offset + source.length;
            const nl = { type: 'newline', offset, indent: token.indent, source: '\n' };
            delete token.items;
            Object.assign(token, { type, source, end: [nl] });
            break;
        }
        default: {
            const indent = 'indent' in token ? token.indent : -1;
            const end = 'end' in token && Array.isArray(token.end)
                ? token.end.filter(st => st.type === 'space' ||
                    st.type === 'comment' ||
                    st.type === 'newline')
                : [];
            for (const key of Object.keys(token))
                if (key !== 'type' && key !== 'offset')
                    delete token[key];
            Object.assign(token, { type, indent, source, end });
        }
    }
}

export { createScalarToken, resolveAsScalar, setScalarValue };


code:
/**
 * Stringify a CST document, token, or collection item
 *
 * Fair warning: This applies no validation whatsoever, and
 * simply concatenates the sources in their logical order.
 */
const stringify = (cst) => 'type' in cst ? stringifyToken(cst) : stringifyItem(cst);
function stringifyToken(token) {
    switch (token.type) {
        case 'block-scalar': {
            let res = '';
            for (const tok of token.props)
                res += stringifyToken(tok);
            return res + token.source;
        }
        case 'block-map':
        case 'block-seq': {
            let res = '';
            for (const item of token.items)
                res += stringifyItem(item);
            return res;
        }
        case 'flow-collection': {
            let res = token.start.source;
            for (const item of token.items)
                res += stringifyItem(item);
            for (const st of token.end)
                res += st.source;
            return res;
        }
        case 'document': {
            let res = stringifyItem(token);
            if (token.end)
                for (const st of token.end)
                    res += st.source;
            return res;
        }
        default: {
            let res = token.source;
            if ('end' in token && token.end)
                for (const st of token.end)
                    res += st.source;
            return res;
        }
    }
}
function stringifyItem({ start, key, sep, value }) {
    let res = '';
    for (const st of start)
        res += st.source;
    if (key)
        res += stringifyToken(key);
    if (sep)
        for (const st of sep)
            res += st.source;
    if (value)
        res += stringifyToken(value);
    return res;
}

export { stringify };


code:
const BREAK = Symbol('break visit');
const SKIP = Symbol('skip children');
const REMOVE = Symbol('remove item');
/**
 * Apply a visitor to a CST document or item.
 *
 * Walks through the tree (depth-first) starting from the root, calling a
 * `visitor` function with two arguments when entering each item:
 *   - `item`: The current item, which included the following members:
 *     - `start: SourceToken[]` – Source tokens before the key or value,
 *       possibly including its anchor or tag.
 *     - `key?: Token | null` – Set for pair values. May then be `null`, if
 *       the key before the `:` separator is empty.
 *     - `sep?: SourceToken[]` – Source tokens between the key and the value,
 *       which should include the `:` map value indicator if `value` is set.
 *     - `value?: Token` – The value of a sequence item, or of a map pair.
 *   - `path`: The steps from the root to the current node, as an array of
 *     `['key' | 'value', number]` tuples.
 *
 * The return value of the visitor may be used to control the traversal:
 *   - `undefined` (default): Do nothing and continue
 *   - `visit.SKIP`: Do not visit the children of this token, continue with
 *      next sibling
 *   - `visit.BREAK`: Terminate traversal completely
 *   - `visit.REMOVE`: Remove the current item, then continue with the next one
 *   - `number`: Set the index of the next step. This is useful especially if
 *     the index of the current token has changed.
 *   - `function`: Define the next visitor for this item. After the original
 *     visitor is called on item entry, next visitors are called after handling
 *     a non-empty `key` and when exiting the item.
 */
function visit(cst, visitor) {
    if ('type' in cst && cst.type === 'document')
        cst = { start: cst.start, value: cst.value };
    _visit(Object.freeze([]), cst, visitor);
}
// Without the `as symbol` casts, TS declares these in the `visit`
// namespace using `var`, but then complains about that because
// `unique symbol` must be `const`.
/** Terminate visit traversal completely */
visit.BREAK = BREAK;
/** Do not visit the children of the current item */
visit.SKIP = SKIP;
/** Remove the current item */
visit.REMOVE = REMOVE;
/** Find the item at `path` from `cst` as the root */
visit.itemAtPath = (cst, path) => {
    let item = cst;
    for (const [field, index] of path) {
        const tok = item?.[field];
        if (tok && 'items' in tok) {
            item = tok.items[index];
        }
        else
            return undefined;
    }
    return item;
};
/**
 * Get the immediate parent collection of the item at `path` from `cst` as the root.
 *
 * Throws an error if the collection is not found, which should never happen if the item itself exists.
 */
visit.parentCollection = (cst, path) => {
    const parent = visit.itemAtPath(cst, path.slice(0, -1));
    const field = path[path.length - 1][0];
    const coll = parent?.[field];
    if (coll && 'items' in coll)
        return coll;
    throw new Error('Parent collection not found');
};
function _visit(path, item, visitor) {
    let ctrl = visitor(item, path);
    if (typeof ctrl === 'symbol')
        return ctrl;
    for (const field of ['key', 'value']) {
        const token = item[field];
        if (token && 'items' in token) {
            for (let i = 0; i < token.items.length; ++i) {
                const ci = _visit(Object.freeze(path.concat([[field, i]])), token.items[i], visitor);
                if (typeof ci === 'number')
                    i = ci - 1;
                else if (ci === BREAK)
                    return BREAK;
                else if (ci === REMOVE) {
                    token.items.splice(i, 1);
                    i -= 1;
                }
            }
            if (typeof ctrl === 'function' && field === 'key')
                ctrl = ctrl(item, path);
        }
    }
    return typeof ctrl === 'function' ? ctrl(item, path) : ctrl;
}

export { visit };


code:
export { createScalarToken, resolveAsScalar, setScalarValue } from './cst-scalar.js';
export { stringify } from './cst-stringify.js';
export { visit } from './cst-visit.js';

/** The byte order mark */
const BOM = '\u{FEFF}';
/** Start of doc-mode */
const DOCUMENT = '\x02'; // C0: Start of Text
/** Unexpected end of flow-mode */
const FLOW_END = '\x18'; // C0: Cancel
/** Next token is a scalar value */
const SCALAR = '\x1f'; // C0: Unit Separator
/** @returns `true` if `token` is a flow or block collection */
const isCollection = (token) => !!token && 'items' in token;
/** @returns `true` if `token` is a flow or block scalar; not an alias */
const isScalar = (token) => !!token &&
    (token.type === 'scalar' ||
        token.type === 'single-quoted-scalar' ||
        token.type === 'double-quoted-scalar' ||
        token.type === 'block-scalar');
/* istanbul ignore next */
/** Get a printable representation of a lexer token */
function prettyToken(token) {
    switch (token) {
        case BOM:
            return '<BOM>';
        case DOCUMENT:
            return '<DOC>';
        case FLOW_END:
            return '<FLOW_END>';
        case SCALAR:
            return '<SCALAR>';
        default:
            return JSON.stringify(token);
    }
}
/** Identify the type of a lexer token. May return `null` for unknown tokens. */
function tokenType(source) {
    switch (source) {
        case BOM:
            return 'byte-order-mark';
        case DOCUMENT:
            return 'doc-mode';
        case FLOW_END:
            return 'flow-error-end';
        case SCALAR:
            return 'scalar';
        case '---':
            return 'doc-start';
        case '...':
            return 'doc-end';
        case '':
        case '\n':
        case '\r\n':
            return 'newline';
        case '-':
            return 'seq-item-ind';
        case '?':
            return 'explicit-key-ind';
        case ':':
            return 'map-value-ind';
        case '{':
            return 'flow-map-start';
        case '}':
            return 'flow-map-end';
        case '[':
            return 'flow-seq-start';
        case ']':
            return 'flow-seq-end';
        case ',':
            return 'comma';
    }
    switch (source[0]) {
        case ' ':
        case '\t':
            return 'space';
        case '#':
            return 'comment';
        case '%':
            return 'directive-line';
        case '*':
            return 'alias';
        case '&':
            return 'anchor';
        case '!':
            return 'tag';
        case "'":
            return 'single-quoted-scalar';
        case '"':
            return 'double-quoted-scalar';
        case '|':
        case '>':
            return 'block-scalar-header';
    }
    return null;
}

export { BOM, DOCUMENT, FLOW_END, SCALAR, isCollection, isScalar, prettyToken, tokenType };


code:
import { BOM, DOCUMENT, FLOW_END, SCALAR } from './cst.js';

/*
START -> stream

stream
  directive -> line-end -> stream
  indent + line-end -> stream
  [else] -> line-start

line-end
  comment -> line-end
  newline -> .
  input-end -> END

line-start
  doc-start -> doc
  doc-end -> stream
  [else] -> indent -> block-start

block-start
  seq-item-start -> block-start
  explicit-key-start -> block-start
  map-value-start -> block-start
  [else] -> doc

doc
  line-end -> line-start
  spaces -> doc
  anchor -> doc
  tag -> doc
  flow-start -> flow -> doc
  flow-end -> error -> doc
  seq-item-start -> error -> doc
  explicit-key-start -> error -> doc
  map-value-start -> doc
  alias -> doc
  quote-start -> quoted-scalar -> doc
  block-scalar-header -> line-end -> block-scalar(min) -> line-start
  [else] -> plain-scalar(false, min) -> doc

flow
  line-end -> flow
  spaces -> flow
  anchor -> flow
  tag -> flow
  flow-start -> flow -> flow
  flow-end -> .
  seq-item-start -> error -> flow
  explicit-key-start -> flow
  map-value-start -> flow
  alias -> flow
  quote-start -> quoted-scalar -> flow
  comma -> flow
  [else] -> plain-scalar(true, 0) -> flow

quoted-scalar
  quote-end -> .
  [else] -> quoted-scalar

block-scalar(min)
  newline + peek(indent < min) -> .
  [else] -> block-scalar(min)

plain-scalar(is-flow, min)
  scalar-end(is-flow) -> .
  peek(newline + (indent < min)) -> .
  [else] -> plain-scalar(min)
*/
function isEmpty(ch) {
    switch (ch) {
        case undefined:
        case ' ':
        case '\n':
        case '\r':
        case '\t':
            return true;
        default:
            return false;
    }
}
const hexDigits = new Set('0123456789ABCDEFabcdef');
const tagChars = new Set("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-#;/?:@&=+$_.!~*'()");
const flowIndicatorChars = new Set(',[]{}');
const invalidAnchorChars = new Set(' ,[]{}\n\r\t');
const isNotAnchorChar = (ch) => !ch || invalidAnchorChars.has(ch);
/**
 * Splits an input string into lexical tokens, i.e. smaller strings that are
 * easily identifiable by `tokens.tokenType()`.
 *
 * Lexing starts always in a "stream" context. Incomplete input may be buffered
 * until a complete token can be emitted.
 *
 * In addition to slices of the original input, the following control characters
 * may also be emitted:
 *
 * - `\x02` (Start of Text): A document starts with the next token
 * - `\x18` (Cancel): Unexpected end of flow-mode (indicates an error)
 * - `\x1f` (Unit Separator): Next token is a scalar value
 * - `\u{FEFF}` (Byte order mark): Emitted separately outside documents
 */
class Lexer {
    constructor() {
        /**
         * Flag indicating whether the end of the current buffer marks the end of
         * all input
         */
        this.atEnd = false;
        /**
         * Explicit indent set in block scalar header, as an offset from the current
         * minimum indent, so e.g. set to 1 from a header `|2+`. Set to -1 if not
         * explicitly set.
         */
        this.blockScalarIndent = -1;
        /**
         * Block scalars that include a + (keep) chomping indicator in their header
         * include trailing empty lines, which are otherwise excluded from the
         * scalar's contents.
         */
        this.blockScalarKeep = false;
        /** Current input */
        this.buffer = '';
        /**
         * Flag noting whether the map value indicator : can immediately follow this
         * node within a flow context.
         */
        this.flowKey = false;
        /** Count of surrounding flow collection levels. */
        this.flowLevel = 0;
        /**
         * Minimum level of indentation required for next lines to be parsed as a
         * part of the current scalar value.
         */
        this.indentNext = 0;
        /** Indentation level of the current line. */
        this.indentValue = 0;
        /** Position of the next \n character. */
        this.lineEndPos = null;
        /** Stores the state of the lexer if reaching the end of incpomplete input */
        this.next = null;
        /** A pointer to `buffer`; the current position of the lexer. */
        this.pos = 0;
    }
    /**
     * Generate YAML tokens from the `source` string. If `incomplete`,
     * a part of the last line may be left as a buffer for the next call.
     *
     * @returns A generator of lexical tokens
     */
    *lex(source, incomplete = false) {
        if (source) {
            if (typeof source !== 'string')
                throw TypeError('source is not a string');
            this.buffer = this.buffer ? this.buffer + source : source;
            this.lineEndPos = null;
        }
        this.atEnd = !incomplete;
        let next = this.next ?? 'stream';
        while (next && (incomplete || this.hasChars(1)))
            next = yield* this.parseNext(next);
    }
    atLineEnd() {
        let i = this.pos;
        let ch = this.buffer[i];
        while (ch === ' ' || ch === '\t')
            ch = this.buffer[++i];
        if (!ch || ch === '#' || ch === '\n')
            return true;
        if (ch === '\r')
            return this.buffer[i + 1] === '\n';
        return false;
    }
    charAt(n) {
        return this.buffer[this.pos + n];
    }
    continueScalar(offset) {
        let ch = this.buffer[offset];
        if (this.indentNext > 0) {
            let indent = 0;
            while (ch === ' ')
                ch = this.buffer[++indent + offset];
            if (ch === '\r') {
                const next = this.buffer[indent + offset + 1];
                if (next === '\n' || (!next && !this.atEnd))
                    return offset + indent + 1;
            }
            return ch === '\n' || indent >= this.indentNext || (!ch && !this.atEnd)
                ? offset + indent
                : -1;
        }
        if (ch === '-' || ch === '.') {
            const dt = this.buffer.substr(offset, 3);
            if ((dt === '---' || dt === '...') && isEmpty(this.buffer[offset + 3]))
                return -1;
        }
        return offset;
    }
    getLine() {
        let end = this.lineEndPos;
        if (typeof end !== 'number' || (end !== -1 && end < this.pos)) {
            end = this.buffer.indexOf('\n', this.pos);
            this.lineEndPos = end;
        }
        if (end === -1)
            return this.atEnd ? this.buffer.substring(this.pos) : null;
        if (this.buffer[end - 1] === '\r')
            end -= 1;
        return this.buffer.substring(this.pos, end);
    }
    hasChars(n) {
        return this.pos + n <= this.buffer.length;
    }
    setNext(state) {
        this.buffer = this.buffer.substring(this.pos);
        this.pos = 0;
        this.lineEndPos = null;
        this.next = state;
        return null;
    }
    peek(n) {
        return this.buffer.substr(this.pos, n);
    }
    *parseNext(next) {
        switch (next) {
            case 'stream':
                return yield* this.parseStream();
            case 'line-start':
                return yield* this.parseLineStart();
            case 'block-start':
                return yield* this.parseBlockStart();
            case 'doc':
                return yield* this.parseDocument();
            case 'flow':
                return yield* this.parseFlowCollection();
            case 'quoted-scalar':
                return yield* this.parseQuotedScalar();
            case 'block-scalar':
                return yield* this.parseBlockScalar();
            case 'plain-scalar':
                return yield* this.parsePlainScalar();
        }
    }
    *parseStream() {
        let line = this.getLine();
        if (line === null)
            return this.setNext('stream');
        if (line[0] === BOM) {
            yield* this.pushCount(1);
            line = line.substring(1);
        }
        if (line[0] === '%') {
            let dirEnd = line.length;
            let cs = line.indexOf('#');
            while (cs !== -1) {
                const ch = line[cs - 1];
                if (ch === ' ' || ch === '\t') {
                    dirEnd = cs - 1;
                    break;
                }
                else {
                    cs = line.indexOf('#', cs + 1);
                }
            }
            while (true) {
                const ch = line[dirEnd - 1];
                if (ch === ' ' || ch === '\t')
                    dirEnd -= 1;
                else
                    break;
            }
            const n = (yield* this.pushCount(dirEnd)) + (yield* this.pushSpaces(true));
            yield* this.pushCount(line.length - n); // possible comment
            this.pushNewline();
            return 'stream';
        }
        if (this.atLineEnd()) {
            const sp = yield* this.pushSpaces(true);
            yield* this.pushCount(line.length - sp);
            yield* this.pushNewline();
            return 'stream';
        }
        yield DOCUMENT;
        return yield* this.parseLineStart();
    }
    *parseLineStart() {
        const ch = this.charAt(0);
        if (!ch && !this.atEnd)
            return this.setNext('line-start');
        if (ch === '-' || ch === '.') {
            if (!this.atEnd && !this.hasChars(4))
                return this.setNext('line-start');
            const s = this.peek(3);
            if ((s === '---' || s === '...') && isEmpty(this.charAt(3))) {
                yield* this.pushCount(3);
                this.indentValue = 0;
                this.indentNext = 0;
                return s === '---' ? 'doc' : 'stream';
            }
        }
        this.indentValue = yield* this.pushSpaces(false);
        if (this.indentNext > this.indentValue && !isEmpty(this.charAt(1)))
            this.indentNext = this.indentValue;
        return yield* this.parseBlockStart();
    }
    *parseBlockStart() {
        const [ch0, ch1] = this.peek(2);
        if (!ch1 && !this.atEnd)
            return this.setNext('block-start');
        if ((ch0 === '-' || ch0 === '?' || ch0 === ':') && isEmpty(ch1)) {
            const n = (yield* this.pushCount(1)) + (yield* this.pushSpaces(true));
            this.indentNext = this.indentValue + 1;
            this.indentValue += n;
            return yield* this.parseBlockStart();
        }
        return 'doc';
    }
    *parseDocument() {
        yield* this.pushSpaces(true);
        const line = this.getLine();
        if (line === null)
            return this.setNext('doc');
        let n = yield* this.pushIndicators();
        switch (line[n]) {
            case '#':
                yield* this.pushCount(line.length - n);
            // fallthrough
            case undefined:
                yield* this.pushNewline();
                return yield* this.parseLineStart();
            case '{':
            case '[':
                yield* this.pushCount(1);
                this.flowKey = false;
                this.flowLevel = 1;
                return 'flow';
            case '}':
            case ']':
                // this is an error
                yield* this.pushCount(1);
                return 'doc';
            case '*':
                yield* this.pushUntil(isNotAnchorChar);
                return 'doc';
            case '"':
            case "'":
                return yield* this.parseQuotedScalar();
            case '|':
            case '>':
                n += yield* this.parseBlockScalarHeader();
                n += yield* this.pushSpaces(true);
                yield* this.pushCount(line.length - n);
                yield* this.pushNewline();
                return yield* this.parseBlockScalar();
            default:
                return yield* this.parsePlainScalar();
        }
    }
    *parseFlowCollection() {
        let nl, sp;
        let indent = -1;
        do {
            nl = yield* this.pushNewline();
            if (nl > 0) {
                sp = yield* this.pushSpaces(false);
                this.indentValue = indent = sp;
            }
            else {
                sp = 0;
            }
            sp += yield* this.pushSpaces(true);
        } while (nl + sp > 0);
        const line = this.getLine();
        if (line === null)
            return this.setNext('flow');
        if ((indent !== -1 && indent < this.indentNext && line[0] !== '#') ||
            (indent === 0 &&
                (line.startsWith('---') || line.startsWith('...')) &&
                isEmpty(line[3]))) {
            // Allowing for the terminal ] or } at the same (rather than greater)
            // indent level as the initial [ or { is technically invalid, but
            // failing here would be surprising to users.
            const atFlowEndMarker = indent === this.indentNext - 1 &&
                this.flowLevel === 1 &&
                (line[0] === ']' || line[0] === '}');
            if (!atFlowEndMarker) {
                // this is an error
                this.flowLevel = 0;
                yield FLOW_END;
                return yield* this.parseLineStart();
            }
        }
        let n = 0;
        while (line[n] === ',') {
            n += yield* this.pushCount(1);
            n += yield* this.pushSpaces(true);
            this.flowKey = false;
        }
        n += yield* this.pushIndicators();
        switch (line[n]) {
            case undefined:
                return 'flow';
            case '#':
                yield* this.pushCount(line.length - n);
                return 'flow';
            case '{':
            case '[':
                yield* this.pushCount(1);
                this.flowKey = false;
                this.flowLevel += 1;
                return 'flow';
            case '}':
            case ']':
                yield* this.pushCount(1);
                this.flowKey = true;
                this.flowLevel -= 1;
                return this.flowLevel ? 'flow' : 'doc';
            case '*':
                yield* this.pushUntil(isNotAnchorChar);
                return 'flow';
            case '"':
            case "'":
                this.flowKey = true;
                return yield* this.parseQuotedScalar();
            case ':': {
                const next = this.charAt(1);
                if (this.flowKey || isEmpty(next) || next === ',') {
                    this.flowKey = false;
                    yield* this.pushCount(1);
                    yield* this.pushSpaces(true);
                    return 'flow';
                }
            }
            // fallthrough
            default:
                this.flowKey = false;
                return yield* this.parsePlainScalar();
        }
    }
    *parseQuotedScalar() {
        const quote = this.charAt(0);
        let end = this.buffer.indexOf(quote, this.pos + 1);
        if (quote === "'") {
            while (end !== -1 && this.buffer[end + 1] === "'")
                end = this.buffer.indexOf("'", end + 2);
        }
        else {
            // double-quote
            while (end !== -1) {
                let n = 0;
                while (this.buffer[end - 1 - n] === '\\')
                    n += 1;
                if (n % 2 === 0)
                    break;
                end = this.buffer.indexOf('"', end + 1);
            }
        }
        // Only looking for newlines within the quotes
        const qb = this.buffer.substring(0, end);
        let nl = qb.indexOf('\n', this.pos);
        if (nl !== -1) {
            while (nl !== -1) {
                const cs = this.continueScalar(nl + 1);
                if (cs === -1)
                    break;
                nl = qb.indexOf('\n', cs);
            }
            if (nl !== -1) {
                // this is an error caused by an unexpected unindent
                end = nl - (qb[nl - 1] === '\r' ? 2 : 1);
            }
        }
        if (end === -1) {
            if (!this.atEnd)
                return this.setNext('quoted-scalar');
            end = this.buffer.length;
        }
        yield* this.pushToIndex(end + 1, false);
        return this.flowLevel ? 'flow' : 'doc';
    }
    *parseBlockScalarHeader() {
        this.blockScalarIndent = -1;
        this.blockScalarKeep = false;
        let i = this.pos;
        while (true) {
            const ch = this.buffer[++i];
            if (ch === '+')
                this.blockScalarKeep = true;
            else if (ch > '0' && ch <= '9')
                this.blockScalarIndent = Number(ch) - 1;
            else if (ch !== '-')
                break;
        }
        return yield* this.pushUntil(ch => isEmpty(ch) || ch === '#');
    }
    *parseBlockScalar() {
        let nl = this.pos - 1; // may be -1 if this.pos === 0
        let indent = 0;
        let ch;
        loop: for (let i = this.pos; (ch = this.buffer[i]); ++i) {
            switch (ch) {
                case ' ':
                    indent += 1;
                    break;
                case '\n':
                    nl = i;
                    indent = 0;
                    break;
                case '\r': {
                    const next = this.buffer[i + 1];
                    if (!next && !this.atEnd)
                        return this.setNext('block-scalar');
                    if (next === '\n')
                        break;
                } // fallthrough
                default:
                    break loop;
            }
        }
        if (!ch && !this.atEnd)
            return this.setNext('block-scalar');
        if (indent >= this.indentNext) {
            if (this.blockScalarIndent === -1)
                this.indentNext = indent;
            else {
                this.indentNext =
                    this.blockScalarIndent + (this.indentNext === 0 ? 1 : this.indentNext);
            }
            do {
                const cs = this.continueScalar(nl + 1);
                if (cs === -1)
                    break;
                nl = this.buffer.indexOf('\n', cs);
            } while (nl !== -1);
            if (nl === -1) {
                if (!this.atEnd)
                    return this.setNext('block-scalar');
                nl = this.buffer.length;
            }
        }
        // Trailing insufficiently indented tabs are invalid.
        // To catch that during parsing, we include them in the block scalar value.
        let i = nl + 1;
        ch = this.buffer[i];
        while (ch === ' ')
            ch = this.buffer[++i];
        if (ch === '\t') {
            while (ch === '\t' || ch === ' ' || ch === '\r' || ch === '\n')
                ch = this.buffer[++i];
            nl = i - 1;
        }
        else if (!this.blockScalarKeep) {
            do {
                let i = nl - 1;
                let ch = this.buffer[i];
                if (ch === '\r')
                    ch = this.buffer[--i];
                const lastChar = i; // Drop the line if last char not more indented
                while (ch === ' ')
                    ch = this.buffer[--i];
                if (ch === '\n' && i >= this.pos && i + 1 + indent > lastChar)
                    nl = i;
                else
                    break;
            } while (true);
        }
        yield SCALAR;
        yield* this.pushToIndex(nl + 1, true);
        return yield* this.parseLineStart();
    }
    *parsePlainScalar() {
        const inFlow = this.flowLevel > 0;
        let end = this.pos - 1;
        let i = this.pos - 1;
        let ch;
        while ((ch = this.buffer[++i])) {
            if (ch === ':') {
                const next = this.buffer[i + 1];
                if (isEmpty(next) || (inFlow && flowIndicatorChars.has(next)))
                    break;
                end = i;
            }
            else if (isEmpty(ch)) {
                let next = this.buffer[i + 1];
                if (ch === '\r') {
                    if (next === '\n') {
                        i += 1;
                        ch = '\n';
                        next = this.buffer[i + 1];
                    }
                    else
                        end = i;
                }
                if (next === '#' || (inFlow && flowIndicatorChars.has(next)))
                    break;
                if (ch === '\n') {
                    const cs = this.continueScalar(i + 1);
                    if (cs === -1)
                        break;
                    i = Math.max(i, cs - 2); // to advance, but still account for ' #'
                }
            }
            else {
                if (inFlow && flowIndicatorChars.has(ch))
                    break;
                end = i;
            }
        }
        if (!ch && !this.atEnd)
            return this.setNext('plain-scalar');
        yield SCALAR;
        yield* this.pushToIndex(end + 1, true);
        return inFlow ? 'flow' : 'doc';
    }
    *pushCount(n) {
        if (n > 0) {
            yield this.buffer.substr(this.pos, n);
            this.pos += n;
            return n;
        }
        return 0;
    }
    *pushToIndex(i, allowEmpty) {
        const s = this.buffer.slice(this.pos, i);
        if (s) {
            yield s;
            this.pos += s.length;
            return s.length;
        }
        else if (allowEmpty)
            yield '';
        return 0;
    }
    *pushIndicators() {
        switch (this.charAt(0)) {
            case '!':
                return ((yield* this.pushTag()) +
                    (yield* this.pushSpaces(true)) +
                    (yield* this.pushIndicators()));
            case '&':
                return ((yield* this.pushUntil(isNotAnchorChar)) +
                    (yield* this.pushSpaces(true)) +
                    (yield* this.pushIndicators()));
            case '-': // this is an error
            case '?': // this is an error outside flow collections
            case ':': {
                const inFlow = this.flowLevel > 0;
                const ch1 = this.charAt(1);
                if (isEmpty(ch1) || (inFlow && flowIndicatorChars.has(ch1))) {
                    if (!inFlow)
                        this.indentNext = this.indentValue + 1;
                    else if (this.flowKey)
                        this.flowKey = false;
                    return ((yield* this.pushCount(1)) +
                        (yield* this.pushSpaces(true)) +
                        (yield* this.pushIndicators()));
                }
            }
        }
        return 0;
    }
    *pushTag() {
        if (this.charAt(1) === '<') {
            let i = this.pos + 2;
            let ch = this.buffer[i];
            while (!isEmpty(ch) && ch !== '>')
                ch = this.buffer[++i];
            return yield* this.pushToIndex(ch === '>' ? i + 1 : i, false);
        }
        else {
            let i = this.pos + 1;
            let ch = this.buffer[i];
            while (ch) {
                if (tagChars.has(ch))
                    ch = this.buffer[++i];
                else if (ch === '%' &&
                    hexDigits.has(this.buffer[i + 1]) &&
                    hexDigits.has(this.buffer[i + 2])) {
                    ch = this.buffer[(i += 3)];
                }
                else
                    break;
            }
            return yield* this.pushToIndex(i, false);
        }
    }
    *pushNewline() {
        const ch = this.buffer[this.pos];
        if (ch === '\n')
            return yield* this.pushCount(1);
        else if (ch === '\r' && this.charAt(1) === '\n')
            return yield* this.pushCount(2);
        else
            return 0;
    }
    *pushSpaces(allowTabs) {
        let i = this.pos - 1;
        let ch;
        do {
            ch = this.buffer[++i];
        } while (ch === ' ' || (allowTabs && ch === '\t'));
        const n = i - this.pos;
        if (n > 0) {
            yield this.buffer.substr(this.pos, n);
            this.pos = i;
        }
        return n;
    }
    *pushUntil(test) {
        let i = this.pos;
        let ch = this.buffer[i];
        while (!test(ch))
            ch = this.buffer[++i];
        return yield* this.pushToIndex(i, false);
    }
}

export { Lexer };