code:
2.6.9 / 2017-09-22
==================

  * remove ReDoS regexp in %o formatter (#504)

2.6.8 / 2017-05-18
==================

  * Fix: Check for undefined on browser globals (#462, @marbemac)

2.6.7 / 2017-05-16
==================

  * Fix: Update ms to 2.0.0 to fix regular expression denial of service vulnerability (#458, @hubdotcom)
  * Fix: Inline extend function in node implementation (#452, @dougwilson)
  * Docs: Fix typo (#455, @msasad)

2.6.5 / 2017-04-27
==================

  * Fix: null reference check on window.documentElement.style.WebkitAppearance (#447, @thebigredgeek)
  * Misc: clean up browser reference checks (#447, @thebigredgeek)
  * Misc: add npm-debug.log to .gitignore (@thebigredgeek)

2.6.4 / 2017-04-20
==================

  * Fix: bug that would occure if process.env.DEBUG is a non-string value. (#444, @LucianBuzzo)
  * Chore: ignore bower.json in npm installations. (#437, @joaovieira)
  * Misc: update "ms" to v0.7.3 (@tootallnate)

2.6.3 / 2017-03-13
==================

  * Fix: Electron reference to `process.env.DEBUG` (#431, @paulcbetts)
  * Docs: Changelog fix (@thebigredgeek)

2.6.2 / 2017-03-10
==================

  * Fix: DEBUG_MAX_ARRAY_LENGTH (#420, @slavaGanzin)
  * Docs: Add backers and sponsors from Open Collective (#422, @piamancini)
  * Docs: Add Slackin invite badge (@tootallnate)

2.6.1 / 2017-02-10
==================

  * Fix: Module's `export default` syntax fix for IE8 `Expected identifier` error
  * Fix: Whitelist DEBUG_FD for values 1 and 2 only (#415, @pi0)
  * Fix: IE8 "Expected identifier" error (#414, @vgoma)
  * Fix: Namespaces would not disable once enabled (#409, @musikov)

2.6.0 / 2016-12-28
==================

  * Fix: added better null pointer checks for browser useColors (@thebigredgeek)
  * Improvement: removed explicit `window.debug` export (#404, @tootallnate)
  * Improvement: deprecated `DEBUG_FD` environment variable (#405, @tootallnate)

2.5.2 / 2016-12-25
==================

  * Fix: reference error on window within webworkers (#393, @KlausTrainer)
  * Docs: fixed README typo (#391, @lurch)
  * Docs: added notice about v3 api discussion (@thebigredgeek)

2.5.1 / 2016-12-20
==================

  * Fix: babel-core compatibility

2.5.0 / 2016-12-20
==================

  * Fix: wrong reference in bower file (@thebigredgeek)
  * Fix: webworker compatibility (@thebigredgeek)
  * Fix: output formatting issue (#388, @kribblo)
  * Fix: babel-loader compatibility (#383, @escwald)
  * Misc: removed built asset from repo and publications (@thebigredgeek)
  * Misc: moved source files to /src (#378, @yamikuronue)
  * Test: added karma integration and replaced babel with browserify for browser tests (#378, @yamikuronue)
  * Test: coveralls integration (#378, @yamikuronue)
  * Docs: simplified language in the opening paragraph (#373, @yamikuronue)

2.4.5 / 2016-12-17
==================

  * Fix: `navigator` undefined in Rhino (#376, @jochenberger)
  * Fix: custom log function (#379, @hsiliev)
  * Improvement: bit of cleanup + linting fixes (@thebigredgeek)
  * Improvement: rm non-maintainted `dist/` dir (#375, @freewil)
  * Docs: simplified language in the opening paragraph. (#373, @yamikuronue)

2.4.4 / 2016-12-14
==================

  * Fix: work around debug being loaded in preload scripts for electron (#368, @paulcbetts)

2.4.3 / 2016-12-14
==================

  * Fix: navigation.userAgent error for react native (#364, @escwald)

2.4.2 / 2016-12-14
==================

  * Fix: browser colors (#367, @tootallnate)
  * Misc: travis ci integration (@thebigredgeek)
  * Misc: added linting and testing boilerplate with sanity check (@thebigredgeek)

2.4.1 / 2016-12-13
==================

  * Fix: typo that broke the package (#356)

2.4.0 / 2016-12-13
==================

  * Fix: bower.json references unbuilt src entry point (#342, @justmatt)
  * Fix: revert "handle regex special characters" (@tootallnate)
  * Feature: configurable util.inspect()`options for NodeJS (#327, @tootallnate)
  * Feature: %O`(big O) pretty-prints objects (#322, @tootallnate)
  * Improvement: allow colors in workers (#335, @botverse)
  * Improvement: use same color for same namespace. (#338, @lchenay)

2.3.3 / 2016-11-09
==================

  * Fix: Catch `JSON.stringify()` errors (#195, Jovan Alleyne)
  * Fix: Returning `localStorage` saved values (#331, Levi Thomason)
  * Improvement: Don't create an empty object when no `process` (Nathan Rajlich)

2.3.2 / 2016-11-09
==================

  * Fix: be super-safe in index.js as well (@TooTallNate)
  * Fix: should check whether process exists (Tom Newby)

2.3.1 / 2016-11-09
==================

  * Fix: Added electron compatibility (#324, @paulcbetts)
  * Improvement: Added performance optimizations (@tootallnate)
  * Readme: Corrected PowerShell environment variable example (#252, @gimre)
  * Misc: Removed yarn lock file from source control (#321, @fengmk2)

2.3.0 / 2016-11-07
==================

  * Fix: Consistent placement of ms diff at end of output (#215, @gorangajic)
  * Fix: Escaping of regex special characters in namespace strings (#250, @zacronos)
  * Fix: Fixed bug causing crash on react-native (#282, @vkarpov15)
  * Feature: Enabled ES6+ compatible import via default export (#212 @bucaran)
  * Feature: Added %O formatter to reflect Chrome's console.log capability (#279, @oncletom)
  * Package: Update "ms" to 0.7.2 (#315, @DevSide)
  * Package: removed superfluous version property from bower.json (#207 @kkirsche)
  * Readme: fix USE_COLORS to DEBUG_COLORS
  * Readme: Doc fixes for format string sugar (#269, @mlucool)
  * Readme: Updated docs for DEBUG_FD and DEBUG_COLORS environment variables (#232, @mattlyons0)
  * Readme: doc fixes for PowerShell (#271 #243, @exoticknight @unreadable)
  * Readme: better docs for browser support (#224, @matthewmueller)
  * Tooling: Added yarn integration for development (#317, @thebigredgeek)
  * Misc: Renamed History.md to CHANGELOG.md (@thebigredgeek)
  * Misc: Added license file (#226 #274, @CantemoInternal @sdaitzman)
  * Misc: Updated contributors (@thebigredgeek)

2.2.0 / 2015-05-09
==================

  * package: update "ms" to v0.7.1 (#202, @dougwilson)
  * README: add logging to file example (#193, @DanielOchoa)
  * README: fixed a typo (#191, @amir-s)
  * browser: expose `storage` (#190, @stephenmathieson)
  * Makefile: add a `distclean` target (#189, @stephenmathieson)

2.1.3 / 2015-03-13
==================

  * Updated stdout/stderr example (#186)
  * Updated example/stdout.js to match debug current behaviour
  * Renamed example/stderr.js to stdout.js
  * Update Readme.md (#184)
  * replace high intensity foreground color for bold (#182, #183)

2.1.2 / 2015-03-01
==================

  * dist: recompile
  * update "ms" to v0.7.0
  * package: update "browserify" to v9.0.3
  * component: fix "ms.js" repo location
  * changed bower package name
  * updated documentation about using debug in a browser
  * fix: security error on safari (#167, #168, @yields)

2.1.1 / 2014-12-29
==================

  * browser: use `typeof` to check for `console` existence
  * browser: check for `console.log` truthiness (fix IE 8/9)
  * browser: add support for Chrome apps
  * Readme: added Windows usage remarks
  * Add `bower.json` to properly support bower install

2.1.0 / 2014-10-15
==================

  * node: implement `DEBUG_FD` env variable support
  * package: update "browserify" to v6.1.0
  * package: add "license" field to package.json (#135, @panuhorsmalahti)

2.0.0 / 2014-09-01
==================

  * package: update "browserify" to v5.11.0
  * node: use stderr rather than stdout for logging (#29, @stephenmathieson)

1.0.4 / 2014-07-15
==================

  * dist: recompile
  * example: remove `console.info()` log usage
  * example: add "Content-Type" UTF-8 header to browser example
  * browser: place %c marker after the space character
  * browser: reset the "content" color via `color: inherit`
  * browser: add colors support for Firefox >= v31
  * debug: prefer an instance `log()` function over the global one (#119)
  * Readme: update documentation about styled console logs for FF v31 (#116, @wryk)

1.0.3 / 2014-07-09
==================

  * Add support for multiple wildcards in namespaces (#122, @seegno)
  * browser: fix lint

1.0.2 / 2014-06-10
==================

  * browser: update color palette (#113, @gscottolson)
  * common: make console logging function configurable (#108, @timoxley)
  * node: fix %o colors on old node <= 0.8.x
  * Makefile: find node path using shell/which (#109, @timoxley)

1.0.1 / 2014-06-06
==================

  * browser: use `removeItem()` to clear localStorage
  * browser, node: don't set DEBUG if namespaces is undefined (#107, @leedm777)
  * package: add "contributors" section
  * node: fix comment typo
  * README: list authors

1.0.0 / 2014-06-04
==================

  * make ms diff be global, not be scope
  * debug: ignore empty strings in enable()
  * node: make DEBUG_COLORS able to disable coloring
  * *: export the `colors` array
  * npmignore: don't publish the `dist` dir
  * Makefile: refactor to use browserify
  * package: add "browserify" as a dev dependency
  * Readme: add Web Inspector Colors section
  * node: reset terminal color for the debug content
  * node: map "%o" to `util.inspect()`
  * browser: map "%j" to `JSON.stringify()`
  * debug: add custom "formatters"
  * debug: use "ms" module for humanizing the diff
  * Readme: add "bash" syntax highlighting
  * browser: add Firebug color support
  * browser: add colors for WebKit browsers
  * node: apply log to `console`
  * rewrite: abstract common logic for Node & browsers
  * add .jshintrc file

0.8.1 / 2014-04-14
==================

  * package: re-add the "component" section

0.8.0 / 2014-03-30
==================

  * add `enable()` method for nodejs. Closes #27
  * change from stderr to stdout
  * remove unnecessary index.js file

0.7.4 / 2013-11-13
==================

  * remove "browserify" key from package.json (fixes something in browserify)

0.7.3 / 2013-10-30
==================

  * fix: catch localStorage security error when cookies are blocked (Chrome)
  * add debug(err) support. Closes #46
  * add .browser prop to package.json. Closes #42

0.7.2 / 2013-02-06
==================

  * fix package.json
  * fix: Mobile Safari (private mode) is broken with debug
  * fix: Use unicode to send escape character to shell instead of octal to work with strict mode javascript

0.7.1 / 2013-02-05
==================

  * add repository URL to package.json
  * add DEBUG_COLORED to force colored output
  * add browserify support
  * fix component. Closes #24

0.7.0 / 2012-05-04
==================

  * Added .component to package.json
  * Added debug.component.js build

0.6.0 / 2012-03-16
==================

  * Added support for "-" prefix in DEBUG [Vinay Pulim]
  * Added `.enabled` flag to the node version [TooTallNate]

0.5.0 / 2012-02-02
==================

  * Added: humanize diffs. Closes #8
  * Added `debug.disable()` to the CS variant
  * Removed padding. Closes #10
  * Fixed: persist client-side variant again. Closes #9

0.4.0 / 2012-02-01
==================

  * Added browser variant support for older browsers [TooTallNate]
  * Added `debug.enable('project:*')` to browser variant [TooTallNate]
  * Added padding to diff (moved it to the right)

0.3.0 / 2012-01-26
==================

  * Added millisecond diff when isatty, otherwise UTC string

0.2.0 / 2012-01-22
==================

  * Added wildcard support

0.1.0 / 2011-12-02
==================

  * Added: remove colors unless stderr isatty [TooTallNate]

0.0.1 / 2010-01-03
==================

  * Initial release


code:
# get Makefile directory name: http://stackoverflow.com/a/5982798/376773
THIS_MAKEFILE_PATH:=$(word $(words $(MAKEFILE_LIST)),$(MAKEFILE_LIST))
THIS_DIR:=$(shell cd $(dir $(THIS_MAKEFILE_PATH));pwd)

# BIN directory
BIN := $(THIS_DIR)/node_modules/.bin

# Path
PATH := node_modules/.bin:$(PATH)
SHELL := /bin/bash

# applications
NODE ?= $(shell which node)
YARN ?= $(shell which yarn)
PKG ?= $(if $(YARN),$(YARN),$(NODE) $(shell which npm))
BROWSERIFY ?= $(NODE) $(BIN)/browserify

.FORCE:

install: node_modules

node_modules: package.json
	@NODE_ENV= $(PKG) install
	@touch node_modules

lint: .FORCE
	eslint browser.js debug.js index.js node.js

test-node: .FORCE
	istanbul cover node_modules/mocha/bin/_mocha -- test/**.js

test-browser: .FORCE
	mkdir -p dist

	@$(BROWSERIFY) \
		--standalone debug \
		. > dist/debug.js

	karma start --single-run
	rimraf dist

test: .FORCE
	concurrently \
		"make test-node" \
		"make test-browser"

coveralls:
	cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js

.PHONY: all install clean distclean

license: mit


code:
# debug
[![Build Status](https://travis-ci.org/visionmedia/debug.svg?branch=master)](https://travis-ci.org/visionmedia/debug)  [![Coverage Status](https://coveralls.io/repos/github/visionmedia/debug/badge.svg?branch=master)](https://coveralls.io/github/visionmedia/debug?branch=master)  [![Slack](https://visionmedia-community-slackin.now.sh/badge.svg)](https://visionmedia-community-slackin.now.sh/) [![OpenCollective](https://opencollective.com/debug/backers/badge.svg)](#backers)
[![OpenCollective](https://opencollective.com/debug/sponsors/badge.svg)](#sponsors)

A tiny node.js debugging utility modelled after node core's debugging technique.

**Discussion around the V3 API is under way [here](https://github.com/visionmedia/debug/issues/370)**

## Installation

```bash
$ npm install debug
```

## Usage

`debug` exposes a function; simply pass this function the name of your module, and it will return a decorated version of `console.error` for you to pass debug statements to. This will allow you to toggle the debug output for different parts of your module as well as the module as a whole.

Example _app.js_:

```js
var debug = require('debug')('http')
  , http = require('http')
  , name = 'My App';

// fake app

debug('booting %s', name);

http.createServer(function(req, res){
  debug(req.method + ' ' + req.url);
  res.end('hello\n');
}).listen(3000, function(){
  debug('listening');
});

// fake worker of some kind

require('./worker');
```

Example _worker.js_:

```js
var debug = require('debug')('worker');

setInterval(function(){
  debug('doing some work');
}, 1000);
```

 The __DEBUG__ environment variable is then used to enable these based on space or comma-delimited names. Here are some examples:

  ![debug http and worker](http://f.cl.ly/items/18471z1H402O24072r1J/Screenshot.png)

  ![debug worker](http://f.cl.ly/items/1X413v1a3M0d3C2c1E0i/Screenshot.png)

#### Windows note

 On Windows the environment variable is set using the `set` command.

 ```cmd
 set DEBUG=*,-not_this
 ```

 Note that PowerShell uses different syntax to set environment variables.

 ```cmd
 $env:DEBUG = "*,-not_this"
  ```

Then, run the program to be debugged as usual.

## Millisecond diff

  When actively developing an application it can be useful to see when the time spent between one `debug()` call and the next. Suppose for example you invoke `debug()` before requesting a resource, and after as well, the "+NNNms" will show you how much time was spent between calls.

  ![](http://f.cl.ly/items/2i3h1d3t121M2Z1A3Q0N/Screenshot.png)

  When stdout is not a TTY, `Date#toUTCString()` is used, making it more useful for logging the debug information as shown below:

  ![](http://f.cl.ly/items/112H3i0e0o0P0a2Q2r11/Screenshot.png)

## Conventions

  If you're using this in one or more of your libraries, you _should_ use the name of your library so that developers may toggle debugging as desired without guessing names. If you have more than one debuggers you _should_ prefix them with your library name and use ":" to separate features. For example "bodyParser" from Connect would then be "connect:bodyParser".

## Wildcards

  The `*` character may be used as a wildcard. Suppose for example your library has debuggers named "connect:bodyParser", "connect:compress", "connect:session", instead of listing all three with `DEBUG=connect:bodyParser,connect:compress,connect:session`, you may simply do `DEBUG=connect:*`, or to run everything using this module simply use `DEBUG=*`.

  You can also exclude specific debuggers by prefixing them with a "-" character.  For example, `DEBUG=*,-connect:*` would include all debuggers except those starting with "connect:".

## Environment Variables

  When running through Node.js, you can set a few environment variables that will
  change the behavior of the debug logging:

| Name      | Purpose                                         |
|-----------|-------------------------------------------------|
| `DEBUG`   | Enables/disables specific debugging namespaces. |
| `DEBUG_COLORS`| Whether or not to use colors in the debug output. |
| `DEBUG_DEPTH` | Object inspection depth. |
| `DEBUG_SHOW_HIDDEN` | Shows hidden properties on inspected objects. |

  __Note:__ The environment variables beginning with `DEBUG_` end up being
  converted into an Options object that gets used with `%o`/`%O` formatters.
  See the Node.js documentation for
  [`util.inspect()`](https://nodejs.org/api/util.html#util_util_inspect_object_options)
  for the complete list.

## Formatters

  Debug uses [printf-style](https://wikipedia.org/wiki/Printf_format_string) formatting. Below are the officially supported formatters:

| Formatter | Representation |
|-----------|----------------|
| `%O`      | Pretty-print an Object on multiple lines. |
| `%o`      | Pretty-print an Object all on a single line. |
| `%s`      | String. |
| `%d`      | Number (both integer and float). |
| `%j`      | JSON. Replaced with the string '[Circular]' if the argument contains circular references. |
| `%%`      | Single percent sign ('%'). This does not consume an argument. |

### Custom formatters

  You can add custom formatters by extending the `debug.formatters` object. For example, if you wanted to add support for rendering a Buffer as hex with `%h`, you could do something like:

```js
const createDebug = require('debug')
createDebug.formatters.h = (v) => {
  return v.toString('hex')
}

// …elsewhere
const debug = createDebug('foo')
debug('this is hex: %h', new Buffer('hello world'))
//   foo this is hex: 68656c6c6f20776f726c6421 +0ms
```

## Browser support
  You can build a browser-ready script using [browserify](https://github.com/substack/node-browserify),
  or just use the [browserify-as-a-service](https://wzrd.in/) [build](https://wzrd.in/standalone/debug@latest),
  if you don't want to build it yourself.

  Debug's enable state is currently persisted by `localStorage`.
  Consider the situation shown below where you have `worker:a` and `worker:b`,
  and wish to debug both. You can enable this using `localStorage.debug`:

```js
localStorage.debug = 'worker:*'
```

And then refresh the page.

```js
a = debug('worker:a');
b = debug('worker:b');

setInterval(function(){
  a('doing some work');
}, 1000);

setInterval(function(){
  b('doing some work');
}, 1200);
```

#### Web Inspector Colors

  Colors are also enabled on "Web Inspectors" that understand the `%c` formatting
  option. These are WebKit web inspectors, Firefox ([since version
  31](https://hacks.mozilla.org/2014/05/editable-box-model-multiple-selection-sublime-text-keys-much-more-firefox-developer-tools-episode-31/))
  and the Firebug plugin for Firefox (any version).

  Colored output looks something like:

  ![](https://cloud.githubusercontent.com/assets/71256/3139768/b98c5fd8-e8ef-11e3-862a-f7253b6f47c6.png)

## Output streams

  By default `debug` will log to stderr, however this can be configured per-namespace by overriding the `log` method:

Example _stdout.js_:

```js
var debug = require('debug');
var error = debug('app:error');

// by default stderr is used
error('goes to stderr!');

var log = debug('app:log');
// set this namespace to log via console.log
log.log = console.log.bind(console); // don't forget to bind to console!
log('goes to stdout');
error('still goes to stderr!');

// set all output to go via console.info
// overrides all per-namespace log settings
debug.log = console.info.bind(console);
error('now goes to stdout via console.info');
log('still goes to stdout, but via console.info now');
```

## Authors

 - TJ Holowaychuk
 - Nathan Rajlich
 - Andrew Rhyne

## Backers

Support us with a monthly donation and help us continue our activities. [[Become a backer](https://opencollective.com/debug#backer)]

## Sponsors

Become a sponsor and get your logo on our README on Github with a link to your site. [[Become a sponsor](https://opencollective.com/debug#sponsor)]

## License

(The MIT License)

Copyright (c) 2014-2016 TJ Holowaychuk <tj@vision-media.ca>

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
'Software'), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


debug

repo: visionmedia/debug

description: small debugging utility

keywords: debug log debugger


code:
// Karma configuration
// Generated on Fri Dec 16 2016 13:09:51 GMT+0000 (UTC)

module.exports = function(config) {
  config.set({

    // base path that will be used to resolve all patterns (eg. files, exclude)
    basePath: '',

    // frameworks to use
    // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
    frameworks: ['mocha', 'chai', 'sinon'],

    // list of files / patterns to load in the browser
    files: [
      'dist/debug.js',
      'test/*spec.js'
    ],

    // list of files to exclude
    exclude: [
      'src/node.js'
    ],

    // preprocess matching files before serving them to the browser
    // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
    preprocessors: {
    },

    // test results reporter to use
    // possible values: 'dots', 'progress'
    // available reporters: https://npmjs.org/browse/keyword/karma-reporter
    reporters: ['progress'],

    // web server port
    port: 9876,

    // enable / disable colors in the output (reporters and logs)
    colors: true,

    // level of logging
    // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
    logLevel: config.LOG_INFO,

    // enable / disable watching file and executing tests whenever any file changes
    autoWatch: true,

    // start these browsers
    // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
    browsers: ['PhantomJS'],

    // Continuous Integration mode
    // if true, Karma captures browsers, runs the tests and exits
    singleRun: false,

    // Concurrency level
    // how many browser should be started simultaneous
    concurrency: Infinity
  })
}


code: module.exports = require('./src/node');


type: git

description: small debugging utility

author: TJ Holowaychuk <tj@vision-media.ca>

contributors: Nathan Rajlich <nathan@tootallnate.net> (http://n8.io)

license: MIT


code:
/**
 * This is the web browser implementation of `debug()`.
 *
 * Expose `debug()` as the module.
 */

exports = module.exports = require('./debug');
exports.log = log;
exports.formatArgs = formatArgs;
exports.save = save;
exports.load = load;
exports.useColors = useColors;
exports.storage = 'undefined' != typeof chrome
               && 'undefined' != typeof chrome.storage
                  ? chrome.storage.local
                  : localstorage();

/**
 * Colors.
 */

exports.colors = [
  'lightseagreen',
  'forestgreen',
  'goldenrod',
  'dodgerblue',
  'darkorchid',
  'crimson'
];

/**
 * Currently only WebKit-based Web Inspectors, Firefox >= v31,
 * and the Firebug extension (any Firefox version) are known
 * to support "%c" CSS customizations.
 *
 * TODO: add a `localStorage` variable to explicitly enable/disable colors
 */

function useColors() {
  // NB: In an Electron preload script, document will be defined but not fully
  // initialized. Since we know we're in Chrome, we'll just detect this case
  // explicitly
  if (typeof window !== 'undefined' && window.process && window.process.type === 'renderer') {
    return true;
  }

  // is webkit? http://stackoverflow.com/a/16459606/376773
  // document is undefined in react-native: https://github.com/facebook/react-native/pull/1632
  return (typeof document !== 'undefined' && document.documentElement && document.documentElement.style && document.documentElement.style.WebkitAppearance) ||
    // is firebug? http://stackoverflow.com/a/398120/376773
    (typeof window !== 'undefined' && window.console && (window.console.firebug || (window.console.exception && window.console.table))) ||
    // is firefox >= v31?
    // https://developer.mozilla.org/en-US/docs/Tools/Web_Console#Styling_messages
    (typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/firefox\/(\d+)/) && parseInt(RegExp.$1, 10) >= 31) ||
    // double check webkit in userAgent just in case we are in a worker
    (typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/applewebkit\/(\d+)/));
}

/**
 * Map %j to `JSON.stringify()`, since no Web Inspectors do that by default.
 */

exports.formatters.j = function(v) {
  try {
    return JSON.stringify(v);
  } catch (err) {
    return '[UnexpectedJSONParseError]: ' + err.message;
  }
};

/**
 * Colorize log arguments if enabled.
 *
 * @api public
 */

function formatArgs(args) {
  var useColors = this.useColors;

  args[0] = (useColors ? '%c' : '')
    + this.namespace
    + (useColors ? ' %c' : ' ')
    + args[0]
    + (useColors ? '%c ' : ' ')
    + '+' + exports.humanize(this.diff);

  if (!useColors) return;

  var c = 'color: ' + this.color;
  args.splice(1, 0, c, 'color: inherit')

  // the final "%c" is somewhat tricky, because there could be other
  // arguments passed either before or after the %c, so we need to
  // figure out the correct index to insert the CSS into
  var index = 0;
  var lastC = 0;
  args[0].replace(/%[a-zA-Z%]/g, function(match) {
    if ('%%' === match) return;
    index++;
    if ('%c' === match) {
      // we only are interested in the *last* %c
      // (the user may have provided their own)
      lastC = index;
    }
  });

  args.splice(lastC, 0, c);
}

/**
 * Invokes `console.log()` when available.
 * No-op when `console.log` is not a "function".
 *
 * @api public
 */

function log() {
  // this hackery is required for IE8/9, where
  // the `console.log` function doesn't have 'apply'
  return 'object' === typeof console
    && console.log
    && Function.prototype.apply.call(console.log, console, arguments);
}

/**
 * Save `namespaces`.
 *
 * @param {String} namespaces
 * @api private
 */

function save(namespaces) {
  try {
    if (null == namespaces) {
      exports.storage.removeItem('debug');
    } else {
      exports.storage.debug = namespaces;
    }
  } catch(e) {}
}

/**
 * Load `namespaces`.
 *
 * @return {String} returns the previously persisted debug modes
 * @api private
 */

function load() {
  var r;
  try {
    r = exports.storage.debug;
  } catch(e) {}

  // If debug isn't set in LS, and we're in Electron, try to load $DEBUG
  if (!r && typeof process !== 'undefined' && 'env' in process) {
    r = process.env.DEBUG;
  }

  return r;
}

/**
 * Enable namespaces listed in `localStorage.debug` initially.
 */

exports.enable(load());

/**
 * Localstorage attempts to return the localstorage.
 *
 * This is necessary because safari throws
 * when a user disables cookies/localstorage
 * and you attempt to access it.
 *
 * @return {LocalStorage}
 * @api private
 */

function localstorage() {
  try {
    return window.localStorage;
  } catch (e) {}
}


code:
/**
 * This is the common logic for both the Node.js and web browser
 * implementations of `debug()`.
 *
 * Expose `debug()` as the module.
 */

exports = module.exports = createDebug.debug = createDebug['default'] = createDebug;
exports.coerce = coerce;
exports.disable = disable;
exports.enable = enable;
exports.enabled = enabled;
exports.humanize = require('ms');

/**
 * The currently active debug mode names, and names to skip.
 */

exports.names = [];
exports.skips = [];

/**
 * Map of special "%n" handling functions, for the debug "format" argument.
 *
 * Valid key names are a single, lower or upper-case letter, i.e. "n" and "N".
 */

exports.formatters = {};

/**
 * Previous log timestamp.
 */

var prevTime;

/**
 * Select a color.
 * @param {String} namespace
 * @return {Number}
 * @api private
 */

function selectColor(namespace) {
  var hash = 0, i;

  for (i in namespace) {
    hash  = ((hash << 5) - hash) + namespace.charCodeAt(i);
    hash |= 0; // Convert to 32bit integer
  }

  return exports.colors[Math.abs(hash) % exports.colors.length];
}

/**
 * Create a debugger with the given `namespace`.
 *
 * @param {String} namespace
 * @return {Function}
 * @api public
 */

function createDebug(namespace) {

  function debug() {
    // disabled?
    if (!debug.enabled) return;

    var self = debug;

    // set `diff` timestamp
    var curr = +new Date();
    var ms = curr - (prevTime || curr);
    self.diff = ms;
    self.prev = prevTime;
    self.curr = curr;
    prevTime = curr;

    // turn the `arguments` into a proper Array
    var args = new Array(arguments.length);
    for (var i = 0; i < args.length; i++) {
      args[i] = arguments[i];
    }

    args[0] = exports.coerce(args[0]);

    if ('string' !== typeof args[0]) {
      // anything else let's inspect with %O
      args.unshift('%O');
    }

    // apply any `formatters` transformations
    var index = 0;
    args[0] = args[0].replace(/%([a-zA-Z%])/g, function(match, format) {
      // if we encounter an escaped % then don't increase the array index
      if (match === '%%') return match;
      index++;
      var formatter = exports.formatters[format];
      if ('function' === typeof formatter) {
        var val = args[index];
        match = formatter.call(self, val);

        // now we need to remove `args[index]` since it's inlined in the `format`
        args.splice(index, 1);
        index--;
      }
      return match;
    });

    // apply env-specific formatting (colors, etc.)
    exports.formatArgs.call(self, args);

    var logFn = debug.log || exports.log || console.log.bind(console);
    logFn.apply(self, args);
  }

  debug.namespace = namespace;
  debug.enabled = exports.enabled(namespace);
  debug.useColors = exports.useColors();
  debug.color = selectColor(namespace);

  // env-specific initialization logic for debug instances
  if ('function' === typeof exports.init) {
    exports.init(debug);
  }

  return debug;
}

/**
 * Enables a debug mode by namespaces. This can include modes
 * separated by a colon and wildcards.
 *
 * @param {String} namespaces
 * @api public
 */

function enable(namespaces) {
  exports.save(namespaces);

  exports.names = [];
  exports.skips = [];

  var split = (typeof namespaces === 'string' ? namespaces : '').split(/[\s,]+/);
  var len = split.length;

  for (var i = 0; i < len; i++) {
    if (!split[i]) continue; // ignore empty strings
    namespaces = split[i].replace(/\*/g, '.*?');
    if (namespaces[0] === '-') {
      exports.skips.push(new RegExp('^' + namespaces.substr(1) + '$'));
    } else {
      exports.names.push(new RegExp('^' + namespaces + '$'));
    }
  }
}

/**
 * Disable debug output.
 *
 * @api public
 */

function disable() {
  exports.enable('');
}

/**
 * Returns true if the given mode name is enabled, false otherwise.
 *
 * @param {String} name
 * @return {Boolean}
 * @api public
 */

function enabled(name) {
  var i, len;
  for (i = 0, len = exports.skips.length; i < len; i++) {
    if (exports.skips[i].test(name)) {
      return false;
    }
  }
  for (i = 0, len = exports.names.length; i < len; i++) {
    if (exports.names[i].test(name)) {
      return true;
    }
  }
  return false;
}

/**
 * Coerce `val`.
 *
 * @param {Mixed} val
 * @return {Mixed}
 * @api private
 */

function coerce(val) {
  if (val instanceof Error) return val.stack || val.message;
  return val;
}


code:
/**
 * Detect Electron renderer process, which is node, but we should
 * treat as a browser.
 */

if (typeof process !== 'undefined' && process.type === 'renderer') {
  module.exports = require('./browser.js');
} else {
  module.exports = require('./node.js');
}


code:
module.exports = inspectorLog;

// black hole
const nullStream = new (require('stream').Writable)();
nullStream._write = () => {};

/**
 * Outputs a `console.log()` to the Node.js Inspector console *only*.
 */
function inspectorLog() {
  const stdout = console._stdout;
  console._stdout = nullStream;
  console.log.apply(console, arguments);
  console._stdout = stdout;
}


code:
/**
 * Module dependencies.
 */

var tty = require('tty');
var util = require('util');

/**
 * This is the Node.js implementation of `debug()`.
 *
 * Expose `debug()` as the module.
 */

exports = module.exports = require('./debug');
exports.init = init;
exports.log = log;
exports.formatArgs = formatArgs;
exports.save = save;
exports.load = load;
exports.useColors = useColors;

/**
 * Colors.
 */

exports.colors = [6, 2, 3, 4, 5, 1];

/**
 * Build up the default `inspectOpts` object from the environment variables.
 *
 *   $ DEBUG_COLORS=no DEBUG_DEPTH=10 DEBUG_SHOW_HIDDEN=enabled node script.js
 */

exports.inspectOpts = Object.keys(process.env).filter(function (key) {
  return /^debug_/i.test(key);
}).reduce(function (obj, key) {
  // camel-case
  var prop = key
    .substring(6)
    .toLowerCase()
    .replace(/_([a-z])/g, function (_, k) { return k.toUpperCase() });

  // coerce string value into JS value
  var val = process.env[key];
  if (/^(yes|on|true|enabled)$/i.test(val)) val = true;
  else if (/^(no|off|false|disabled)$/i.test(val)) val = false;
  else if (val === 'null') val = null;
  else val = Number(val);

  obj[prop] = val;
  return obj;
}, {});

/**
 * The file descriptor to write the `debug()` calls to.
 * Set the `DEBUG_FD` env variable to override with another value. i.e.:
 *
 *   $ DEBUG_FD=3 node script.js 3>debug.log
 */

var fd = parseInt(process.env.DEBUG_FD, 10) || 2;

if (1 !== fd && 2 !== fd) {
  util.deprecate(function(){}, 'except for stderr(2) and stdout(1), any other usage of DEBUG_FD is deprecated. Override debug.log if you want to use a different log function (https://git.io/debug_fd)')()
}

var stream = 1 === fd ? process.stdout :
             2 === fd ? process.stderr :
             createWritableStdioStream(fd);

/**
 * Is stdout a TTY? Colored output is enabled when `true`.
 */

function useColors() {
  return 'colors' in exports.inspectOpts
    ? Boolean(exports.inspectOpts.colors)
    : tty.isatty(fd);
}

/**
 * Map %o to `util.inspect()`, all on a single line.
 */

exports.formatters.o = function(v) {
  this.inspectOpts.colors = this.useColors;
  return util.inspect(v, this.inspectOpts)
    .split('\n').map(function(str) {
      return str.trim()
    }).join(' ');
};

/**
 * Map %o to `util.inspect()`, allowing multiple lines if needed.
 */

exports.formatters.O = function(v) {
  this.inspectOpts.colors = this.useColors;
  return util.inspect(v, this.inspectOpts);
};

/**
 * Adds ANSI color escape codes if enabled.
 *
 * @api public
 */

function formatArgs(args) {
  var name = this.namespace;
  var useColors = this.useColors;

  if (useColors) {
    var c = this.color;
    var prefix = '  \u001b[3' + c + ';1m' + name + ' ' + '\u001b[0m';

    args[0] = prefix + args[0].split('\n').join('\n' + prefix);
    args.push('\u001b[3' + c + 'm+' + exports.humanize(this.diff) + '\u001b[0m');
  } else {
    args[0] = new Date().toUTCString()
      + ' ' + name + ' ' + args[0];
  }
}

/**
 * Invokes `util.format()` with the specified arguments and writes to `stream`.
 */

function log() {
  return stream.write(util.format.apply(util, arguments) + '\n');
}

/**
 * Save `namespaces`.
 *
 * @param {String} namespaces
 * @api private
 */

function save(namespaces) {
  if (null == namespaces) {
    // If you set a process.env field to null or undefined, it gets cast to the
    // string 'null' or 'undefined'. Just delete instead.
    delete process.env.DEBUG;
  } else {
    process.env.DEBUG = namespaces;
  }
}

/**
 * Load `namespaces`.
 *
 * @return {String} returns the previously persisted debug modes
 * @api private
 */

function load() {
  return process.env.DEBUG;
}

/**
 * Copied from `node/src/node.js`.
 *
 * XXX: It's lame that node doesn't expose this API out-of-the-box. It also
 * relies on the undocumented `tty_wrap.guessHandleType()` which is also lame.
 */

function createWritableStdioStream (fd) {
  var stream;
  var tty_wrap = process.binding('tty_wrap');

  // Note stream._type is used for test-module-load-list.js

  switch (tty_wrap.guessHandleType(fd)) {
    case 'TTY':
      stream = new tty.WriteStream(fd);
      stream._type = 'tty';

      // Hack to have stream not keep the event loop alive.
      // See https://github.com/joyent/node/issues/1726
      if (stream._handle && stream._handle.unref) {
        stream._handle.unref();
      }
      break;

    case 'FILE':
      var fs = require('fs');
      stream = new fs.SyncWriteStream(fd, { autoClose: false });
      stream._type = 'fs';
      break;

    case 'PIPE':
    case 'TCP':
      var net = require('net');
      stream = new net.Socket({
        fd: fd,
        readable: false,
        writable: true
      });

      // FIXME Should probably have an option in net.Socket to create a
      // stream from an existing fd which is writable only. But for now
      // we'll just add this hack and set the `readable` member to false.
      // Test: ./node test/fixtures/echo.js < /etc/passwd
      stream.readable = false;
      stream.read = null;
      stream._type = 'pipe';

      // FIXME Hack to have stream not keep the event loop alive.
      // See https://github.com/joyent/node/issues/1726
      if (stream._handle && stream._handle.unref) {
        stream._handle.unref();
      }
      break;

    default:
      // Probably an error on in uv_guess_handle()
      throw new Error('Implement me. Unknown stream file type!');
  }

  // For supporting legacy API we put the FD here.
  stream.fd = fd;

  stream._isStdio = true;

  return stream;
}

/**
 * Init logic for `debug` instances.
 *
 * Create a new `inspectOpts` object in case `useColors` is set
 * differently for a particular `debug` instance.
 */

function init (debug) {
  debug.inspectOpts = {};

  var keys = Object.keys(exports.inspectOpts);
  for (var i = 0; i < keys.length; i++) {
    debug.inspectOpts[keys[i]] = exports.inspectOpts[keys[i]];
  }
}

/**
 * Enable namespaces listed in `process.env.DEBUG` initially.
 */

exports.enable(load());


code:
/**
 * Helpers.
 */

var s = 1000;
var m = s * 60;
var h = m * 60;
var d = h * 24;
var y = d * 365.25;

/**
 * Parse or format the given `val`.
 *
 * Options:
 *
 *  - `long` verbose formatting [false]
 *
 * @param {String|Number} val
 * @param {Object} [options]
 * @throws {Error} throw an error if val is not a non-empty string or a number
 * @return {String|Number}
 * @api public
 */

module.exports = function(val, options) {
  options = options || {};
  var type = typeof val;
  if (type === 'string' && val.length > 0) {
    return parse(val);
  } else if (type === 'number' && isNaN(val) === false) {
    return options.long ? fmtLong(val) : fmtShort(val);
  }
  throw new Error(
    'val is not a non-empty string or a valid number. val=' +
      JSON.stringify(val)
  );
};

/**
 * Parse the given `str` and return milliseconds.
 *
 * @param {String} str
 * @return {Number}
 * @api private
 */

function parse(str) {
  str = String(str);
  if (str.length > 100) {
    return;
  }
  var match = /^((?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|years?|yrs?|y)?$/i.exec(
    str
  );
  if (!match) {
    return;
  }
  var n = parseFloat(match[1]);
  var type = (match[2] || 'ms').toLowerCase();
  switch (type) {
    case 'years':
    case 'year':
    case 'yrs':
    case 'yr':
    case 'y':
      return n * y;
    case 'days':
    case 'day':
    case 'd':
      return n * d;
    case 'hours':
    case 'hour':
    case 'hrs':
    case 'hr':
    case 'h':
      return n * h;
    case 'minutes':
    case 'minute':
    case 'mins':
    case 'min':
    case 'm':
      return n * m;
    case 'seconds':
    case 'second':
    case 'secs':
    case 'sec':
    case 's':
      return n * s;
    case 'milliseconds':
    case 'millisecond':
    case 'msecs':
    case 'msec':
    case 'ms':
      return n;
    default:
      return undefined;
  }
}

/**
 * Short format for `ms`.
 *
 * @param {Number} ms
 * @return {String}
 * @api private
 */

function fmtShort(ms) {
  if (ms >= d) {
    return Math.round(ms / d) + 'd';
  }
  if (ms >= h) {
    return Math.round(ms / h) + 'h';
  }
  if (ms >= m) {
    return Math.round(ms / m) + 'm';
  }
  if (ms >= s) {
    return Math.round(ms / s) + 's';
  }
  return ms + 'ms';
}

/**
 * Long format for `ms`.
 *
 * @param {Number} ms
 * @return {String}
 * @api private
 */

function fmtLong(ms) {
  return plural(ms, d, 'day') ||
    plural(ms, h, 'hour') ||
    plural(ms, m, 'minute') ||
    plural(ms, s, 'second') ||
    ms + ' ms';
}

/**
 * Pluralization helper.
 */

function plural(ms, n, name) {
  if (ms < n) {
    return;
  }
  if (ms < n * 1.5) {
    return Math.floor(ms / n) + ' ' + name;
  }
  return Math.ceil(ms / n) + ' ' + name + 's';
}


ms

description: Tiny milisecond conversion utility

repository: zeit/ms

main: ./index

precommit: lint-staged

lint: eslint lib/* bin/*

test: mocha tests.js

*.js:
npm run lint
prettier --single-quote --write
git add


code:
# ms

[![Build Status](https://travis-ci.org/zeit/ms.svg?branch=master)](https://travis-ci.org/zeit/ms)
[![Slack Channel](http://zeit-slackin.now.sh/badge.svg)](https://zeit.chat/)

Use this package to easily convert various time formats to milliseconds.

## Examples

```js
ms('2 days')  // 172800000
ms('1d')      // 86400000
ms('10h')     // 36000000
ms('2.5 hrs') // 9000000
ms('2h')      // 7200000
ms('1m')      // 60000
ms('5s')      // 5000
ms('1y')      // 31557600000
ms('100')     // 100
```

### Convert from milliseconds

```js
ms(60000)             // "1m"
ms(2 * 60000)         // "2m"
ms(ms('10 hours'))    // "10h"
```

### Time format written-out

```js
ms(60000, { long: true })             // "1 minute"
ms(2 * 60000, { long: true })         // "2 minutes"
ms(ms('10 hours'), { long: true })    // "10 hours"
```

## Features

- Works both in [node](https://nodejs.org) and in the browser.
- If a number is supplied to `ms`, a string with a unit is returned.
- If a string that contains the number is supplied, it returns it as a number (e.g.: it returns `100` for `'100'`).
- If you pass a string with a number and a valid unit, the number of equivalent ms is returned.

## Caught a bug?

1. [Fork](https://help.github.com/articles/fork-a-repo/) this repository to your own GitHub account and then [clone](https://help.github.com/articles/cloning-a-repository/) it to your local device
2. Link the package to the global module directory: `npm link`
3. Within the module you want to test your local development instance of ms, just link it to the dependencies: `npm link ms`. Instead of the default one from npm, node will now use your clone of ms!

As always, you can run the tests using: `npm test`


express

description: Fast, unopinionated, minimalist web framework

contributors: Douglas Christopher Wilson <doug@somethingdoug.com>

repository: expressjs/express

keywords: express framework sinatra web http rest restful router app api

lint: eslint .

test: mocha --require test/support/env --reporter spec --bail --check-leaks test/ test/acceptance/

test-ci: nyc --reporter=lcovonly --reporter=text npm test

test-cov: nyc --reporter=html --reporter=text npm test

test-tap: mocha --require test/support/env --reporter tap --check-leaks test/ test/acceptance/


code:
# fast-deep-equal
The fastest deep equal with ES6 Map, Set and Typed arrays support.

[![Build Status](https://travis-ci.org/epoberezkin/fast-deep-equal.svg?branch=master)](https://travis-ci.org/epoberezkin/fast-deep-equal)
[![npm](https://img.shields.io/npm/v/fast-deep-equal.svg)](https://www.npmjs.com/package/fast-deep-equal)
[![Coverage Status](https://coveralls.io/repos/github/epoberezkin/fast-deep-equal/badge.svg?branch=master)](https://coveralls.io/github/epoberezkin/fast-deep-equal?branch=master)

## Install

```bash
npm install fast-deep-equal
```

## Features

- ES5 compatible
- works in node.js (8+) and browsers (IE9+)
- checks equality of Date and RegExp objects by value.

ES6 equal (`require('fast-deep-equal/es6')`) also supports:
- Maps
- Sets
- Typed arrays

## Usage

```javascript
var equal = require('fast-deep-equal');
console.log(equal({foo: 'bar'}, {foo: 'bar'})); // true
```

To support ES6 Maps, Sets and Typed arrays equality use:

```javascript
var equal = require('fast-deep-equal/es6');
console.log(equal(Int16Array([1, 2]), Int16Array([1, 2]))); // true
```

To use with React (avoiding the traversal of React elements' _owner
property that contains circular references and is not needed when
comparing the elements - borrowed from [react-fast-compare](https://github.com/FormidableLabs/react-fast-compare)):

```javascript
var equal = require('fast-deep-equal/react');
var equal = require('fast-deep-equal/es6/react');
```

## Performance benchmark

Node.js v12.6.0:

```
fast-deep-equal x 261,950 ops/sec ±0.52% (89 runs sampled)
fast-deep-equal/es6 x 212,991 ops/sec ±0.34% (92 runs sampled)
fast-equals x 230,957 ops/sec ±0.83% (85 runs sampled)
nano-equal x 187,995 ops/sec ±0.53% (88 runs sampled)
shallow-equal-fuzzy x 138,302 ops/sec ±0.49% (90 runs sampled)
underscore.isEqual x 74,423 ops/sec ±0.38% (89 runs sampled)
lodash.isEqual x 36,637 ops/sec ±0.72% (90 runs sampled)
deep-equal x 2,310 ops/sec ±0.37% (90 runs sampled)
deep-eql x 35,312 ops/sec ±0.67% (91 runs sampled)
ramda.equals x 12,054 ops/sec ±0.40% (91 runs sampled)
util.isDeepStrictEqual x 46,440 ops/sec ±0.43% (90 runs sampled)
assert.deepStrictEqual x 456 ops/sec ±0.71% (88 runs sampled)

The fastest is fast-deep-equal
```

To run benchmark (requires node.js 6+):

```bash
npm run benchmark
```

__Please note__: this benchmark runs against the available test cases. To choose the most performant library for your application, it is recommended to benchmark against your data and to NOT expect this benchmark to reflect the performance difference in your application.

## Enterprise support

fast-deep-equal package is a part of [Tidelift enterprise subscription](https://tidelift.com/subscription/pkg/npm-fast-deep-equal?utm_source=npm-fast-deep-equal&utm_medium=referral&utm_campaign=enterprise&utm_term=repo) - it provides a centralised commercial support to open-source software users, in addition to the support provided by software maintainers.

## Security contact

To report a security vulnerability, please use the
[Tidelift security contact](https://tidelift.com/security).
Tidelift will coordinate the fix and disclosure. Please do NOT report security vulnerability via GitHub issues.

## License

[MIT](https://github.com/epoberezkin/fast-deep-equal/blob/master/LICENSE)


code:
declare const equal: (a: any, b: any) => boolean;
export = equal;


code:
'use strict';

// do not edit .js files directly - edit src/index.jst

  var envHasBigInt64Array = typeof BigInt64Array !== 'undefined';

module.exports = function equal(a, b) {
  if (a === b) return true;

  if (a && b && typeof a == 'object' && typeof b == 'object') {
    if (a.constructor !== b.constructor) return false;

    var length, i, keys;
    if (Array.isArray(a)) {
      length = a.length;
      if (length != b.length) return false;
      for (i = length; i-- !== 0;)
        if (!equal(a[i], b[i])) return false;
      return true;
    }

    if ((a instanceof Map) && (b instanceof Map)) {
      if (a.size !== b.size) return false;
      for (i of a.entries())
        if (!b.has(i[0])) return false;
      for (i of a.entries())
        if (!equal(i[1], b.get(i[0]))) return false;
      return true;
    }

    if ((a instanceof Set) && (b instanceof Set)) {
      if (a.size !== b.size) return false;
      for (i of a.entries())
        if (!b.has(i[0])) return false;
      return true;
    }

    if (ArrayBuffer.isView(a) && ArrayBuffer.isView(b)) {
      length = a.length;
      if (length != b.length) return false;
      for (i = length; i-- !== 0;)
        if (a[i] !== b[i]) return false;
      return true;
    }

    if (a.constructor === RegExp) return a.source === b.source && a.flags === b.flags;
    if (a.valueOf !== Object.prototype.valueOf) return a.valueOf() === b.valueOf();
    if (a.toString !== Object.prototype.toString) return a.toString() === b.toString();

    keys = Object.keys(a);
    length = keys.length;
    if (length !== Object.keys(b).length) return false;

    for (i = length; i-- !== 0;)
      if (!Object.prototype.hasOwnProperty.call(b, keys[i])) return false;

    for (i = length; i-- !== 0;) {
      var key = keys[i];

      if (!equal(a[key], b[key])) return false;
    }

    return true;
  }

  // true if both NaN, false otherwise
  return a!==a && b!==b;
};


code:
'use strict';

// do not edit .js files directly - edit src/index.jst

  var envHasBigInt64Array = typeof BigInt64Array !== 'undefined';

module.exports = function equal(a, b) {
  if (a === b) return true;

  if (a && b && typeof a == 'object' && typeof b == 'object') {
    if (a.constructor !== b.constructor) return false;

    var length, i, keys;
    if (Array.isArray(a)) {
      length = a.length;
      if (length != b.length) return false;
      for (i = length; i-- !== 0;)
        if (!equal(a[i], b[i])) return false;
      return true;
    }

    if ((a instanceof Map) && (b instanceof Map)) {
      if (a.size !== b.size) return false;
      for (i of a.entries())
        if (!b.has(i[0])) return false;
      for (i of a.entries())
        if (!equal(i[1], b.get(i[0]))) return false;
      return true;
    }

    if ((a instanceof Set) && (b instanceof Set)) {
      if (a.size !== b.size) return false;
      for (i of a.entries())
        if (!b.has(i[0])) return false;
      return true;
    }

    if (ArrayBuffer.isView(a) && ArrayBuffer.isView(b)) {
      length = a.length;
      if (length != b.length) return false;
      for (i = length; i-- !== 0;)
        if (a[i] !== b[i]) return false;
      return true;
    }

    if (a.constructor === RegExp) return a.source === b.source && a.flags === b.flags;
    if (a.valueOf !== Object.prototype.valueOf) return a.valueOf() === b.valueOf();
    if (a.toString !== Object.prototype.toString) return a.toString() === b.toString();

    keys = Object.keys(a);
    length = keys.length;
    if (length !== Object.keys(b).length) return false;

    for (i = length; i-- !== 0;)
      if (!Object.prototype.hasOwnProperty.call(b, keys[i])) return false;

    for (i = length; i-- !== 0;) {
      var key = keys[i];

      if (key === '_owner' && a.$$typeof) {
        // React-specific: avoid traversing React elements' _owner.
        //  _owner contains circular references
        // and is not needed when comparing the actual elements (and not their owners)
        continue;
      }

      if (!equal(a[key], b[key])) return false;
    }

    return true;
  }

  // true if both NaN, false otherwise
  return a!==a && b!==b;
};


code:
declare module 'fast-deep-equal' {
    const equal: (a: any, b: any) => boolean;
    export = equal;
}


code:
'use strict';

// do not edit .js files directly - edit src/index.jst

module.exports = function equal(a, b) {
  if (a === b) return true;

  if (a && b && typeof a == 'object' && typeof b == 'object') {
    if (a.constructor !== b.constructor) return false;

    var length, i, keys;
    if (Array.isArray(a)) {
      length = a.length;
      if (length != b.length) return false;
      for (i = length; i-- !== 0;)
        if (!equal(a[i], b[i])) return false;
      return true;
    }

    if (a.constructor === RegExp) return a.source === b.source && a.flags === b.flags;
    if (a.valueOf !== Object.prototype.valueOf) return a.valueOf() === b.valueOf();
    if (a.toString !== Object.prototype.toString) return a.toString() === b.toString();

    keys = Object.keys(a);
    length = keys.length;
    if (length !== Object.keys(b).length) return false;

    for (i = length; i-- !== 0;)
      if (!Object.prototype.hasOwnProperty.call(b, keys[i])) return false;

    for (i = length; i-- !== 0;) {
      var key = keys[i];

      if (!equal(a[key], b[key])) return false;
    }

    return true;
  }

  // true if both NaN, false otherwise
  return a!==a && b!==b;
};


fast-deep-equal

description: Fast deep equal

eslint: eslint *.js benchmark/*.js spec/*.js

build: node build

benchmark: npm i && npm run build && cd ./benchmark && npm i && node ./

test-spec: mocha spec/*.spec.js -R spec

test-cov: nyc npm run test-spec

test-ts: tsc --target ES5 --noImplicitAny index.d.ts

test: npm run build && npm run eslint && npm run test-ts && npm run test-cov

prepublish: npm run build

keywords: fast equal deep-equal

author: Evgeny Poberezkin

reporter: lcov text-summary


code:
'use strict';

// do not edit .js files directly - edit src/index.jst

module.exports = function equal(a, b) {
  if (a === b) return true;

  if (a && b && typeof a == 'object' && typeof b == 'object') {
    if (a.constructor !== b.constructor) return false;

    var length, i, keys;
    if (Array.isArray(a)) {
      length = a.length;
      if (length != b.length) return false;
      for (i = length; i-- !== 0;)
        if (!equal(a[i], b[i])) return false;
      return true;
    }

    if (a.constructor === RegExp) return a.source === b.source && a.flags === b.flags;
    if (a.valueOf !== Object.prototype.valueOf) return a.valueOf() === b.valueOf();
    if (a.toString !== Object.prototype.toString) return a.toString() === b.toString();

    keys = Object.keys(a);
    length = keys.length;
    if (length !== Object.keys(b).length) return false;

    for (i = length; i-- !== 0;)
      if (!Object.prototype.hasOwnProperty.call(b, keys[i])) return false;

    for (i = length; i-- !== 0;) {
      var key = keys[i];

      if (key === '_owner' && a.$$typeof) {
        // React-specific: avoid traversing React elements' _owner.
        //  _owner contains circular references
        // and is not needed when comparing the actual elements (and not their owners)
        continue;
      }

      if (!equal(a[key], b[key])) return false;
    }

    return true;
  }

  // true if both NaN, false otherwise
  return a!==a && b!==b;
};


code:
# Fast Diff ![Build Status](https://github.com/jhchen/fast-diff/actions/workflows/test.yml/badge.svg)

This is a simplified import of the excellent [diff-match-patch](https://code.google.com/p/google-diff-match-patch/) library by [Neil Fraser](https://neil.fraser.name/) into the Node.js environment. The match and patch parts are removed, as well as all the extra diff options. What remains is incredibly fast diffing between two strings.

 The diff function is an implementation of ["An O(ND) Difference Algorithm and its Variations" (Myers, 1986)](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.4.6927&rep=rep1&type=pdf) with the suggested divide and conquer strategy along with several [optimizations](http://neil.fraser.name/news/2007/10/09/) Neil added.

```js
var diff = require('fast-diff');

var good = 'Good dog';
var bad = 'Bad dog';

var result = diff(good, bad);
// [[-1, "Goo"], [1, "Ba"], [0, "d dog"]]

// Respect suggested edit location (cursor position), added in v1.1
diff('aaa', 'aaaa', 1)
// [[0, "a"], [1, "a"], [0, "aa"]]

// For convenience
diff.INSERT === 1;
diff.EQUAL === 0;
diff.DELETE === -1;
```


code:
declare function diff(
  text1: string,
  text2: string,
  cursorPos?: number | diff.CursorInfo,
  cleanup?: boolean
): diff.Diff[];

declare namespace diff {
  type Diff = [-1 | 0 | 1, string];

  const DELETE: -1;
  const INSERT: 1;
  const EQUAL: 0;

  interface CursorInfo {
    oldRange: { index: number; length: number };
    newRange: { index: number; length: number };
  }
}

export = diff;


code:
/**
 * This library modifies the diff-patch-match library by Neil Fraser
 * by removing the patch and match functionality and certain advanced
 * options in the diff function. The original license is as follows:
 *
 * ===
 *
 * Diff Match and Patch
 *
 * Copyright 2006 Google Inc.
 * http://code.google.com/p/google-diff-match-patch/
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * The data structure representing a diff is an array of tuples:
 * [[DIFF_DELETE, 'Hello'], [DIFF_INSERT, 'Goodbye'], [DIFF_EQUAL, ' world.']]
 * which means: delete 'Hello', add 'Goodbye' and keep ' world.'
 */
var DIFF_DELETE = -1;
var DIFF_INSERT = 1;
var DIFF_EQUAL = 0;

/**
 * Find the differences between two texts.  Simplifies the problem by stripping
 * any common prefix or suffix off the texts before diffing.
 * @param {string} text1 Old string to be diffed.
 * @param {string} text2 New string to be diffed.
 * @param {Int|Object} [cursor_pos] Edit position in text1 or object with more info
 * @param {boolean} [cleanup] Apply semantic cleanup before returning.
 * @return {Array} Array of diff tuples.
 */
function diff_main(text1, text2, cursor_pos, cleanup, _fix_unicode) {
  // Check for equality
  if (text1 === text2) {
    if (text1) {
      return [[DIFF_EQUAL, text1]];
    }
    return [];
  }

  if (cursor_pos != null) {
    var editdiff = find_cursor_edit_diff(text1, text2, cursor_pos);
    if (editdiff) {
      return editdiff;
    }
  }

  // Trim off common prefix (speedup).
  var commonlength = diff_commonPrefix(text1, text2);
  var commonprefix = text1.substring(0, commonlength);
  text1 = text1.substring(commonlength);
  text2 = text2.substring(commonlength);

  // Trim off common suffix (speedup).
  commonlength = diff_commonSuffix(text1, text2);
  var commonsuffix = text1.substring(text1.length - commonlength);
  text1 = text1.substring(0, text1.length - commonlength);
  text2 = text2.substring(0, text2.length - commonlength);

  // Compute the diff on the middle block.
  var diffs = diff_compute_(text1, text2);

  // Restore the prefix and suffix.
  if (commonprefix) {
    diffs.unshift([DIFF_EQUAL, commonprefix]);
  }
  if (commonsuffix) {
    diffs.push([DIFF_EQUAL, commonsuffix]);
  }
  diff_cleanupMerge(diffs, _fix_unicode);
  if (cleanup) {
    diff_cleanupSemantic(diffs);
  }
  return diffs;
}

/**
 * Find the differences between two texts.  Assumes that the texts do not
 * have any common prefix or suffix.
 * @param {string} text1 Old string to be diffed.
 * @param {string} text2 New string to be diffed.
 * @return {Array} Array of diff tuples.
 */
function diff_compute_(text1, text2) {
  var diffs;

  if (!text1) {
    // Just add some text (speedup).
    return [[DIFF_INSERT, text2]];
  }

  if (!text2) {
    // Just delete some text (speedup).
    return [[DIFF_DELETE, text1]];
  }

  var longtext = text1.length > text2.length ? text1 : text2;
  var shorttext = text1.length > text2.length ? text2 : text1;
  var i = longtext.indexOf(shorttext);
  if (i !== -1) {
    // Shorter text is inside the longer text (speedup).
    diffs = [
      [DIFF_INSERT, longtext.substring(0, i)],
      [DIFF_EQUAL, shorttext],
      [DIFF_INSERT, longtext.substring(i + shorttext.length)],
    ];
    // Swap insertions for deletions if diff is reversed.
    if (text1.length > text2.length) {
      diffs[0][0] = diffs[2][0] = DIFF_DELETE;
    }
    return diffs;
  }

  if (shorttext.length === 1) {
    // Single character string.
    // After the previous speedup, the character can't be an equality.
    return [
      [DIFF_DELETE, text1],
      [DIFF_INSERT, text2],
    ];
  }

  // Check to see if the problem can be split in two.
  var hm = diff_halfMatch_(text1, text2);
  if (hm) {
    // A half-match was found, sort out the return data.
    var text1_a = hm[0];
    var text1_b = hm[1];
    var text2_a = hm[2];
    var text2_b = hm[3];
    var mid_common = hm[4];
    // Send both pairs off for separate processing.
    var diffs_a = diff_main(text1_a, text2_a);
    var diffs_b = diff_main(text1_b, text2_b);
    // Merge the results.
    return diffs_a.concat([[DIFF_EQUAL, mid_common]], diffs_b);
  }

  return diff_bisect_(text1, text2);
}

/**
 * Find the 'middle snake' of a diff, split the problem in two
 * and return the recursively constructed diff.
 * See Myers 1986 paper: An O(ND) Difference Algorithm and Its Variations.
 * @param {string} text1 Old string to be diffed.
 * @param {string} text2 New string to be diffed.
 * @return {Array} Array of diff tuples.
 * @private
 */
function diff_bisect_(text1, text2) {
  // Cache the text lengths to prevent multiple calls.
  var text1_length = text1.length;
  var text2_length = text2.length;
  var max_d = Math.ceil((text1_length + text2_length) / 2);
  var v_offset = max_d;
  var v_length = 2 * max_d;
  var v1 = new Array(v_length);
  var v2 = new Array(v_length);
  // Setting all elements to -1 is faster in Chrome & Firefox than mixing
  // integers and undefined.
  for (var x = 0; x < v_length; x++) {
    v1[x] = -1;
    v2[x] = -1;
  }
  v1[v_offset + 1] = 0;
  v2[v_offset + 1] = 0;
  var delta = text1_length - text2_length;
  // If the total number of characters is odd, then the front path will collide
  // with the reverse path.
  var front = delta % 2 !== 0;
  // Offsets for start and end of k loop.
  // Prevents mapping of space beyond the grid.
  var k1start = 0;
  var k1end = 0;
  var k2start = 0;
  var k2end = 0;
  for (var d = 0; d < max_d; d++) {
    // Walk the front path one step.
    for (var k1 = -d + k1start; k1 <= d - k1end; k1 += 2) {
      var k1_offset = v_offset + k1;
      var x1;
      if (k1 === -d || (k1 !== d && v1[k1_offset - 1] < v1[k1_offset + 1])) {
        x1 = v1[k1_offset + 1];
      } else {
        x1 = v1[k1_offset - 1] + 1;
      }
      var y1 = x1 - k1;
      while (
        x1 < text1_length &&
        y1 < text2_length &&
        text1.charAt(x1) === text2.charAt(y1)
      ) {
        x1++;
        y1++;
      }
      v1[k1_offset] = x1;
      if (x1 > text1_length) {
        // Ran off the right of the graph.
        k1end += 2;
      } else if (y1 > text2_length) {
        // Ran off the bottom of the graph.
        k1start += 2;
      } else if (front) {
        var k2_offset = v_offset + delta - k1;
        if (k2_offset >= 0 && k2_offset < v_length && v2[k2_offset] !== -1) {
          // Mirror x2 onto top-left coordinate system.
          var x2 = text1_length - v2[k2_offset];
          if (x1 >= x2) {
            // Overlap detected.
            return diff_bisectSplit_(text1, text2, x1, y1);
          }
        }
      }
    }

    // Walk the reverse path one step.
    for (var k2 = -d + k2start; k2 <= d - k2end; k2 += 2) {
      var k2_offset = v_offset + k2;
      var x2;
      if (k2 === -d || (k2 !== d && v2[k2_offset - 1] < v2[k2_offset + 1])) {
        x2 = v2[k2_offset + 1];
      } else {
        x2 = v2[k2_offset - 1] + 1;
      }
      var y2 = x2 - k2;
      while (
        x2 < text1_length &&
        y2 < text2_length &&
        text1.charAt(text1_length - x2 - 1) ===
          text2.charAt(text2_length - y2 - 1)
      ) {
        x2++;
        y2++;
      }
      v2[k2_offset] = x2;
      if (x2 > text1_length) {
        // Ran off the left of the graph.
        k2end += 2;
      } else if (y2 > text2_length) {
        // Ran off the top of the graph.
        k2start += 2;
      } else if (!front) {
        var k1_offset = v_offset + delta - k2;
        if (k1_offset >= 0 && k1_offset < v_length && v1[k1_offset] !== -1) {
          var x1 = v1[k1_offset];
          var y1 = v_offset + x1 - k1_offset;
          // Mirror x2 onto top-left coordinate system.
          x2 = text1_length - x2;
          if (x1 >= x2) {
            // Overlap detected.
            return diff_bisectSplit_(text1, text2, x1, y1);
          }
        }
      }
    }
  }
  // Diff took too long and hit the deadline or
  // number of diffs equals number of characters, no commonality at all.
  return [
    [DIFF_DELETE, text1],
    [DIFF_INSERT, text2],
  ];
}

/**
 * Given the location of the 'middle snake', split the diff in two parts
 * and recurse.
 * @param {string} text1 Old string to be diffed.
 * @param {string} text2 New string to be diffed.
 * @param {number} x Index of split point in text1.
 * @param {number} y Index of split point in text2.
 * @return {Array} Array of diff tuples.
 */
function diff_bisectSplit_(text1, text2, x, y) {
  var text1a = text1.substring(0, x);
  var text2a = text2.substring(0, y);
  var text1b = text1.substring(x);
  var text2b = text2.substring(y);

  // Compute both diffs serially.
  var diffs = diff_main(text1a, text2a);
  var diffsb = diff_main(text1b, text2b);

  return diffs.concat(diffsb);
}

/**
 * Determine the common prefix of two strings.
 * @param {string} text1 First string.
 * @param {string} text2 Second string.
 * @return {number} The number of characters common to the start of each
 *     string.
 */
function diff_commonPrefix(text1, text2) {
  // Quick check for common null cases.
  if (!text1 || !text2 || text1.charAt(0) !== text2.charAt(0)) {
    return 0;
  }
  // Binary search.
  // Performance analysis: http://neil.fraser.name/news/2007/10/09/
  var pointermin = 0;
  var pointermax = Math.min(text1.length, text2.length);
  var pointermid = pointermax;
  var pointerstart = 0;
  while (pointermin < pointermid) {
    if (
      text1.substring(pointerstart, pointermid) ==
      text2.substring(pointerstart, pointermid)
    ) {
      pointermin = pointermid;
      pointerstart = pointermin;
    } else {
      pointermax = pointermid;
    }
    pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin);
  }

  if (is_surrogate_pair_start(text1.charCodeAt(pointermid - 1))) {
    pointermid--;
  }

  return pointermid;
}

/**
 * Determine if the suffix of one string is the prefix of another.
 * @param {string} text1 First string.
 * @param {string} text2 Second string.
 * @return {number} The number of characters common to the end of the first
 *     string and the start of the second string.
 * @private
 */
function diff_commonOverlap_(text1, text2) {
  // Cache the text lengths to prevent multiple calls.
  var text1_length = text1.length;
  var text2_length = text2.length;
  // Eliminate the null case.
  if (text1_length == 0 || text2_length == 0) {
    return 0;
  }
  // Truncate the longer string.
  if (text1_length > text2_length) {
    text1 = text1.substring(text1_length - text2_length);
  } else if (text1_length < text2_length) {
    text2 = text2.substring(0, text1_length);
  }
  var text_length = Math.min(text1_length, text2_length);
  // Quick check for the worst case.
  if (text1 == text2) {
    return text_length;
  }

  // Start by looking for a single character match
  // and increase length until no match is found.
  // Performance analysis: http://neil.fraser.name/news/2010/11/04/
  var best = 0;
  var length = 1;
  while (true) {
    var pattern = text1.substring(text_length - length);
    var found = text2.indexOf(pattern);
    if (found == -1) {
      return best;
    }
    length += found;
    if (
      found == 0 ||
      text1.substring(text_length - length) == text2.substring(0, length)
    ) {
      best = length;
      length++;
    }
  }
}

/**
 * Determine the common suffix of two strings.
 * @param {string} text1 First string.
 * @param {string} text2 Second string.
 * @return {number} The number of characters common to the end of each string.
 */
function diff_commonSuffix(text1, text2) {
  // Quick check for common null cases.
  if (!text1 || !text2 || text1.slice(-1) !== text2.slice(-1)) {
    return 0;
  }
  // Binary search.
  // Performance analysis: http://neil.fraser.name/news/2007/10/09/
  var pointermin = 0;
  var pointermax = Math.min(text1.length, text2.length);
  var pointermid = pointermax;
  var pointerend = 0;
  while (pointermin < pointermid) {
    if (
      text1.substring(text1.length - pointermid, text1.length - pointerend) ==
      text2.substring(text2.length - pointermid, text2.length - pointerend)
    ) {
      pointermin = pointermid;
      pointerend = pointermin;
    } else {
      pointermax = pointermid;
    }
    pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin);
  }

  if (is_surrogate_pair_end(text1.charCodeAt(text1.length - pointermid))) {
    pointermid--;
  }

  return pointermid;
}

/**
 * Do the two texts share a substring which is at least half the length of the
 * longer text?
 * This speedup can produce non-minimal diffs.
 * @param {string} text1 First string.
 * @param {string} text2 Second string.
 * @return {Array.<string>} Five element Array, containing the prefix of
 *     text1, the suffix of text1, the prefix of text2, the suffix of
 *     text2 and the common middle.  Or null if there was no match.
 */
function diff_halfMatch_(text1, text2) {
  var longtext = text1.length > text2.length ? text1 : text2;
  var shorttext = text1.length > text2.length ? text2 : text1;
  if (longtext.length < 4 || shorttext.length * 2 < longtext.length) {
    return null; // Pointless.
  }

  /**
   * Does a substring of shorttext exist within longtext such that the substring
   * is at least half the length of longtext?
   * Closure, but does not reference any external variables.
   * @param {string} longtext Longer string.
   * @param {string} shorttext Shorter string.
   * @param {number} i Start index of quarter length substring within longtext.
   * @return {Array.<string>} Five element Array, containing the prefix of
   *     longtext, the suffix of longtext, the prefix of shorttext, the suffix
   *     of shorttext and the common middle.  Or null if there was no match.
   * @private
   */
  function diff_halfMatchI_(longtext, shorttext, i) {
    // Start with a 1/4 length substring at position i as a seed.
    var seed = longtext.substring(i, i + Math.floor(longtext.length / 4));
    var j = -1;
    var best_common = "";
    var best_longtext_a, best_longtext_b, best_shorttext_a, best_shorttext_b;
    while ((j = shorttext.indexOf(seed, j + 1)) !== -1) {
      var prefixLength = diff_commonPrefix(
        longtext.substring(i),
        shorttext.substring(j)
      );
      var suffixLength = diff_commonSuffix(
        longtext.substring(0, i),
        shorttext.substring(0, j)
      );
      if (best_common.length < suffixLength + prefixLength) {
        best_common =
          shorttext.substring(j - suffixLength, j) +
          shorttext.substring(j, j + prefixLength);
        best_longtext_a = longtext.substring(0, i - suffixLength);
        best_longtext_b = longtext.substring(i + prefixLength);
        best_shorttext_a = shorttext.substring(0, j - suffixLength);
        best_shorttext_b = shorttext.substring(j + prefixLength);
      }
    }
    if (best_common.length * 2 >= longtext.length) {
      return [
        best_longtext_a,
        best_longtext_b,
        best_shorttext_a,
        best_shorttext_b,
        best_common,
      ];
    } else {
      return null;
    }
  }

  // First check if the second quarter is the seed for a half-match.
  var hm1 = diff_halfMatchI_(
    longtext,
    shorttext,
    Math.ceil(longtext.length / 4)
  );
  // Check again based on the third quarter.
  var hm2 = diff_halfMatchI_(
    longtext,
    shorttext,
    Math.ceil(longtext.length / 2)
  );
  var hm;
  if (!hm1 && !hm2) {
    return null;
  } else if (!hm2) {
    hm = hm1;
  } else if (!hm1) {
    hm = hm2;
  } else {
    // Both matched.  Select the longest.
    hm = hm1[4].length > hm2[4].length ? hm1 : hm2;
  }

  // A half-match was found, sort out the return data.
  var text1_a, text1_b, text2_a, text2_b;
  if (text1.length > text2.length) {
    text1_a = hm[0];
    text1_b = hm[1];
    text2_a = hm[2];
    text2_b = hm[3];
  } else {
    text2_a = hm[0];
    text2_b = hm[1];
    text1_a = hm[2];
    text1_b = hm[3];
  }
  var mid_common = hm[4];
  return [text1_a, text1_b, text2_a, text2_b, mid_common];
}

/**
 * Reduce the number of edits by eliminating semantically trivial equalities.
 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
 */
function diff_cleanupSemantic(diffs) {
  var changes = false;
  var equalities = []; // Stack of indices where equalities are found.
  var equalitiesLength = 0; // Keeping our own length var is faster in JS.
  /** @type {?string} */
  var lastequality = null;
  // Always equal to diffs[equalities[equalitiesLength - 1]][1]
  var pointer = 0; // Index of current position.
  // Number of characters that changed prior to the equality.
  var length_insertions1 = 0;
  var length_deletions1 = 0;
  // Number of characters that changed after the equality.
  var length_insertions2 = 0;
  var length_deletions2 = 0;
  while (pointer < diffs.length) {
    if (diffs[pointer][0] == DIFF_EQUAL) {
      // Equality found.
      equalities[equalitiesLength++] = pointer;
      length_insertions1 = length_insertions2;
      length_deletions1 = length_deletions2;
      length_insertions2 = 0;
      length_deletions2 = 0;
      lastequality = diffs[pointer][1];
    } else {
      // An insertion or deletion.
      if (diffs[pointer][0] == DIFF_INSERT) {
        length_insertions2 += diffs[pointer][1].length;
      } else {
        length_deletions2 += diffs[pointer][1].length;
      }
      // Eliminate an equality that is smaller or equal to the edits on both
      // sides of it.
      if (
        lastequality &&
        lastequality.length <=
          Math.max(length_insertions1, length_deletions1) &&
        lastequality.length <= Math.max(length_insertions2, length_deletions2)
      ) {
        // Duplicate record.
        diffs.splice(equalities[equalitiesLength - 1], 0, [
          DIFF_DELETE,
          lastequality,
        ]);
        // Change second copy to insert.
        diffs[equalities[equalitiesLength - 1] + 1][0] = DIFF_INSERT;
        // Throw away the equality we just deleted.
        equalitiesLength--;
        // Throw away the previous equality (it needs to be reevaluated).
        equalitiesLength--;
        pointer = equalitiesLength > 0 ? equalities[equalitiesLength - 1] : -1;
        length_insertions1 = 0; // Reset the counters.
        length_deletions1 = 0;
        length_insertions2 = 0;
        length_deletions2 = 0;
        lastequality = null;
        changes = true;
      }
    }
    pointer++;
  }

  // Normalize the diff.
  if (changes) {
    diff_cleanupMerge(diffs);
  }
  diff_cleanupSemanticLossless(diffs);

  // Find any overlaps between deletions and insertions.
  // e.g: abcxxxxxxdef
  //   -> abcxxxdef
  // e.g: xxxabcdefxxx
  //   -> defxxxabc
  // Only extract an overlap if it is as big as the edit ahead or behind it.
  pointer = 1;
  while (pointer < diffs.length) {
    if (
      diffs[pointer - 1][0] == DIFF_DELETE &&
      diffs[pointer][0] == DIFF_INSERT
    ) {
      var deletion = diffs[pointer - 1][1];
      var insertion = diffs[pointer][1];
      var overlap_length1 = diff_commonOverlap_(deletion, insertion);
      var overlap_length2 = diff_commonOverlap_(insertion, deletion);
      if (overlap_length1 >= overlap_length2) {
        if (
          overlap_length1 >= deletion.length / 2 ||
          overlap_length1 >= insertion.length / 2
        ) {
          // Overlap found.  Insert an equality and trim the surrounding edits.
          diffs.splice(pointer, 0, [
            DIFF_EQUAL,
            insertion.substring(0, overlap_length1),
          ]);
          diffs[pointer - 1][1] = deletion.substring(
            0,
            deletion.length - overlap_length1
          );
          diffs[pointer + 1][1] = insertion.substring(overlap_length1);
          pointer++;
        }
      } else {
        if (
          overlap_length2 >= deletion.length / 2 ||
          overlap_length2 >= insertion.length / 2
        ) {
          // Reverse overlap found.
          // Insert an equality and swap and trim the surrounding edits.
          diffs.splice(pointer, 0, [
            DIFF_EQUAL,
            deletion.substring(0, overlap_length2),
          ]);
          diffs[pointer - 1][0] = DIFF_INSERT;
          diffs[pointer - 1][1] = insertion.substring(
            0,
            insertion.length - overlap_length2
          );
          diffs[pointer + 1][0] = DIFF_DELETE;
          diffs[pointer + 1][1] = deletion.substring(overlap_length2);
          pointer++;
        }
      }
      pointer++;
    }
    pointer++;
  }
}

var nonAlphaNumericRegex_ = /[^a-zA-Z0-9]/;
var whitespaceRegex_ = /\s/;
var linebreakRegex_ = /[\r\n]/;
var blanklineEndRegex_ = /\n\r?\n$/;
var blanklineStartRegex_ = /^\r?\n\r?\n/;

/**
 * Look for single edits surrounded on both sides by equalities
 * which can be shifted sideways to align the edit to a word boundary.
 * e.g: The cat came. -> The cat came.
 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
 */
function diff_cleanupSemanticLossless(diffs) {
  /**
   * Given two strings, compute a score representing whether the internal
   * boundary falls on logical boundaries.
   * Scores range from 6 (best) to 0 (worst).
   * Closure, but does not reference any external variables.
   * @param {string} one First string.
   * @param {string} two Second string.
   * @return {number} The score.
   * @private
   */
  function diff_cleanupSemanticScore_(one, two) {
    if (!one || !two) {
      // Edges are the best.
      return 6;
    }

    // Each port of this function behaves slightly differently due to
    // subtle differences in each language's definition of things like
    // 'whitespace'.  Since this function's purpose is largely cosmetic,
    // the choice has been made to use each language's native features
    // rather than force total conformity.
    var char1 = one.charAt(one.length - 1);
    var char2 = two.charAt(0);
    var nonAlphaNumeric1 = char1.match(nonAlphaNumericRegex_);
    var nonAlphaNumeric2 = char2.match(nonAlphaNumericRegex_);
    var whitespace1 = nonAlphaNumeric1 && char1.match(whitespaceRegex_);
    var whitespace2 = nonAlphaNumeric2 && char2.match(whitespaceRegex_);
    var lineBreak1 = whitespace1 && char1.match(linebreakRegex_);
    var lineBreak2 = whitespace2 && char2.match(linebreakRegex_);
    var blankLine1 = lineBreak1 && one.match(blanklineEndRegex_);
    var blankLine2 = lineBreak2 && two.match(blanklineStartRegex_);

    if (blankLine1 || blankLine2) {
      // Five points for blank lines.
      return 5;
    } else if (lineBreak1 || lineBreak2) {
      // Four points for line breaks.
      return 4;
    } else if (nonAlphaNumeric1 && !whitespace1 && whitespace2) {
      // Three points for end of sentences.
      return 3;
    } else if (whitespace1 || whitespace2) {
      // Two points for whitespace.
      return 2;
    } else if (nonAlphaNumeric1 || nonAlphaNumeric2) {
      // One point for non-alphanumeric.
      return 1;
    }
    return 0;
  }

  var pointer = 1;
  // Intentionally ignore the first and last element (don't need checking).
  while (pointer < diffs.length - 1) {
    if (
      diffs[pointer - 1][0] == DIFF_EQUAL &&
      diffs[pointer + 1][0] == DIFF_EQUAL
    ) {
      // This is a single edit surrounded by equalities.
      var equality1 = diffs[pointer - 1][1];
      var edit = diffs[pointer][1];
      var equality2 = diffs[pointer + 1][1];

      // First, shift the edit as far left as possible.
      var commonOffset = diff_commonSuffix(equality1, edit);
      if (commonOffset) {
        var commonString = edit.substring(edit.length - commonOffset);
        equality1 = equality1.substring(0, equality1.length - commonOffset);
        edit = commonString + edit.substring(0, edit.length - commonOffset);
        equality2 = commonString + equality2;
      }

      // Second, step character by character right, looking for the best fit.
      var bestEquality1 = equality1;
      var bestEdit = edit;
      var bestEquality2 = equality2;
      var bestScore =
        diff_cleanupSemanticScore_(equality1, edit) +
        diff_cleanupSemanticScore_(edit, equality2);
      while (edit.charAt(0) === equality2.charAt(0)) {
        equality1 += edit.charAt(0);
        edit = edit.substring(1) + equality2.charAt(0);
        equality2 = equality2.substring(1);
        var score =
          diff_cleanupSemanticScore_(equality1, edit) +
          diff_cleanupSemanticScore_(edit, equality2);
        // The >= encourages trailing rather than leading whitespace on edits.
        if (score >= bestScore) {
          bestScore = score;
          bestEquality1 = equality1;
          bestEdit = edit;
          bestEquality2 = equality2;
        }
      }

      if (diffs[pointer - 1][1] != bestEquality1) {
        // We have an improvement, save it back to the diff.
        if (bestEquality1) {
          diffs[pointer - 1][1] = bestEquality1;
        } else {
          diffs.splice(pointer - 1, 1);
          pointer--;
        }
        diffs[pointer][1] = bestEdit;
        if (bestEquality2) {
          diffs[pointer + 1][1] = bestEquality2;
        } else {
          diffs.splice(pointer + 1, 1);
          pointer--;
        }
      }
    }
    pointer++;
  }
}

/**
 * Reorder and merge like edit sections.  Merge equalities.
 * Any edit section can move as long as it doesn't cross an equality.
 * @param {Array} diffs Array of diff tuples.
 * @param {boolean} fix_unicode Whether to normalize to a unicode-correct diff
 */
function diff_cleanupMerge(diffs, fix_unicode) {
  diffs.push([DIFF_EQUAL, ""]); // Add a dummy entry at the end.
  var pointer = 0;
  var count_delete = 0;
  var count_insert = 0;
  var text_delete = "";
  var text_insert = "";
  var commonlength;
  while (pointer < diffs.length) {
    if (pointer < diffs.length - 1 && !diffs[pointer][1]) {
      diffs.splice(pointer, 1);
      continue;
    }
    switch (diffs[pointer][0]) {
      case DIFF_INSERT:
        count_insert++;
        text_insert += diffs[pointer][1];
        pointer++;
        break;
      case DIFF_DELETE:
        count_delete++;
        text_delete += diffs[pointer][1];
        pointer++;
        break;
      case DIFF_EQUAL:
        var previous_equality = pointer - count_insert - count_delete - 1;
        if (fix_unicode) {
          // prevent splitting of unicode surrogate pairs.  when fix_unicode is true,
          // we assume that the old and new text in the diff are complete and correct
          // unicode-encoded JS strings, but the tuple boundaries may fall between
          // surrogate pairs.  we fix this by shaving off stray surrogates from the end
          // of the previous equality and the beginning of this equality.  this may create
          // empty equalities or a common prefix or suffix.  for example, if AB and AC are
          // emojis, `[[0, 'A'], [-1, 'BA'], [0, 'C']]` would turn into deleting 'ABAC' and
          // inserting 'AC', and then the common suffix 'AC' will be eliminated.  in this
          // particular case, both equalities go away, we absorb any previous inequalities,
          // and we keep scanning for the next equality before rewriting the tuples.
          if (
            previous_equality >= 0 &&
            ends_with_pair_start(diffs[previous_equality][1])
          ) {
            var stray = diffs[previous_equality][1].slice(-1);
            diffs[previous_equality][1] = diffs[previous_equality][1].slice(
              0,
              -1
            );
            text_delete = stray + text_delete;
            text_insert = stray + text_insert;
            if (!diffs[previous_equality][1]) {
              // emptied out previous equality, so delete it and include previous delete/insert
              diffs.splice(previous_equality, 1);
              pointer--;
              var k = previous_equality - 1;
              if (diffs[k] && diffs[k][0] === DIFF_INSERT) {
                count_insert++;
                text_insert = diffs[k][1] + text_insert;
                k--;
              }
              if (diffs[k] && diffs[k][0] === DIFF_DELETE) {
                count_delete++;
                text_delete = diffs[k][1] + text_delete;
                k--;
              }
              previous_equality = k;
            }
          }
          if (starts_with_pair_end(diffs[pointer][1])) {
            var stray = diffs[pointer][1].charAt(0);
            diffs[pointer][1] = diffs[pointer][1].slice(1);
            text_delete += stray;
            text_insert += stray;
          }
        }
        if (pointer < diffs.length - 1 && !diffs[pointer][1]) {
          // for empty equality not at end, wait for next equality
          diffs.splice(pointer, 1);
          break;
        }
        if (text_delete.length > 0 || text_insert.length > 0) {
          // note that diff_commonPrefix and diff_commonSuffix are unicode-aware
          if (text_delete.length > 0 && text_insert.length > 0) {
            // Factor out any common prefixes.
            commonlength = diff_commonPrefix(text_insert, text_delete);
            if (commonlength !== 0) {
              if (previous_equality >= 0) {
                diffs[previous_equality][1] += text_insert.substring(
                  0,
                  commonlength
                );
              } else {
                diffs.splice(0, 0, [
                  DIFF_EQUAL,
                  text_insert.substring(0, commonlength),
                ]);
                pointer++;
              }
              text_insert = text_insert.substring(commonlength);
              text_delete = text_delete.substring(commonlength);
            }
            // Factor out any common suffixes.
            commonlength = diff_commonSuffix(text_insert, text_delete);
            if (commonlength !== 0) {
              diffs[pointer][1] =
                text_insert.substring(text_insert.length - commonlength) +
                diffs[pointer][1];
              text_insert = text_insert.substring(
                0,
                text_insert.length - commonlength
              );
              text_delete = text_delete.substring(
                0,
                text_delete.length - commonlength
              );
            }
          }
          // Delete the offending records and add the merged ones.
          var n = count_insert + count_delete;
          if (text_delete.length === 0 && text_insert.length === 0) {
            diffs.splice(pointer - n, n);
            pointer = pointer - n;
          } else if (text_delete.length === 0) {
            diffs.splice(pointer - n, n, [DIFF_INSERT, text_insert]);
            pointer = pointer - n + 1;
          } else if (text_insert.length === 0) {
            diffs.splice(pointer - n, n, [DIFF_DELETE, text_delete]);
            pointer = pointer - n + 1;
          } else {
            diffs.splice(
              pointer - n,
              n,
              [DIFF_DELETE, text_delete],
              [DIFF_INSERT, text_insert]
            );
            pointer = pointer - n + 2;
          }
        }
        if (pointer !== 0 && diffs[pointer - 1][0] === DIFF_EQUAL) {
          // Merge this equality with the previous one.
          diffs[pointer - 1][1] += diffs[pointer][1];
          diffs.splice(pointer, 1);
        } else {
          pointer++;
        }
        count_insert = 0;
        count_delete = 0;
        text_delete = "";
        text_insert = "";
        break;
    }
  }
  if (diffs[diffs.length - 1][1] === "") {
    diffs.pop(); // Remove the dummy entry at the end.
  }

  // Second pass: look for single edits surrounded on both sides by equalities
  // which can be shifted sideways to eliminate an equality.
  // e.g: ABAC -> ABAC
  var changes = false;
  pointer = 1;
  // Intentionally ignore the first and last element (don't need checking).
  while (pointer < diffs.length - 1) {
    if (
      diffs[pointer - 1][0] === DIFF_EQUAL &&
      diffs[pointer + 1][0] === DIFF_EQUAL
    ) {
      // This is a single edit surrounded by equalities.
      if (
        diffs[pointer][1].substring(
          diffs[pointer][1].length - diffs[pointer - 1][1].length
        ) === diffs[pointer - 1][1]
      ) {
        // Shift the edit over the previous equality.
        diffs[pointer][1] =
          diffs[pointer - 1][1] +
          diffs[pointer][1].substring(
            0,
            diffs[pointer][1].length - diffs[pointer - 1][1].length
          );
        diffs[pointer + 1][1] = diffs[pointer - 1][1] + diffs[pointer + 1][1];
        diffs.splice(pointer - 1, 1);
        changes = true;
      } else if (
        diffs[pointer][1].substring(0, diffs[pointer + 1][1].length) ==
        diffs[pointer + 1][1]
      ) {
        // Shift the edit over the next equality.
        diffs[pointer - 1][1] += diffs[pointer + 1][1];
        diffs[pointer][1] =
          diffs[pointer][1].substring(diffs[pointer + 1][1].length) +
          diffs[pointer + 1][1];
        diffs.splice(pointer + 1, 1);
        changes = true;
      }
    }
    pointer++;
  }
  // If shifts were made, the diff needs reordering and another shift sweep.
  if (changes) {
    diff_cleanupMerge(diffs, fix_unicode);
  }
}

function is_surrogate_pair_start(charCode) {
  return charCode >= 0xd800 && charCode <= 0xdbff;
}

function is_surrogate_pair_end(charCode) {
  return charCode >= 0xdc00 && charCode <= 0xdfff;
}

function starts_with_pair_end(str) {
  return is_surrogate_pair_end(str.charCodeAt(0));
}

function ends_with_pair_start(str) {
  return is_surrogate_pair_start(str.charCodeAt(str.length - 1));
}

function remove_empty_tuples(tuples) {
  var ret = [];
  for (var i = 0; i < tuples.length; i++) {
    if (tuples[i][1].length > 0) {
      ret.push(tuples[i]);
    }
  }
  return ret;
}

function make_edit_splice(before, oldMiddle, newMiddle, after) {
  if (ends_with_pair_start(before) || starts_with_pair_end(after)) {
    return null;
  }
  return remove_empty_tuples([
    [DIFF_EQUAL, before],
    [DIFF_DELETE, oldMiddle],
    [DIFF_INSERT, newMiddle],
    [DIFF_EQUAL, after],
  ]);
}

function find_cursor_edit_diff(oldText, newText, cursor_pos) {
  // note: this runs after equality check has ruled out exact equality
  var oldRange =
    typeof cursor_pos === "number"
      ? { index: cursor_pos, length: 0 }
      : cursor_pos.oldRange;
  var newRange = typeof cursor_pos === "number" ? null : cursor_pos.newRange;
  // take into account the old and new selection to generate the best diff
  // possible for a text edit.  for example, a text change from "xxx" to "xx"
  // could be a delete or forwards-delete of any one of the x's, or the
  // result of selecting two of the x's and typing "x".
  var oldLength = oldText.length;
  var newLength = newText.length;
  if (oldRange.length === 0 && (newRange === null || newRange.length === 0)) {
    // see if we have an insert or delete before or after cursor
    var oldCursor = oldRange.index;
    var oldBefore = oldText.slice(0, oldCursor);
    var oldAfter = oldText.slice(oldCursor);
    var maybeNewCursor = newRange ? newRange.index : null;
    editBefore: {
      // is this an insert or delete right before oldCursor?
      var newCursor = oldCursor + newLength - oldLength;
      if (maybeNewCursor !== null && maybeNewCursor !== newCursor) {
        break editBefore;
      }
      if (newCursor < 0 || newCursor > newLength) {
        break editBefore;
      }
      var newBefore = newText.slice(0, newCursor);
      var newAfter = newText.slice(newCursor);
      if (newAfter !== oldAfter) {
        break editBefore;
      }
      var prefixLength = Math.min(oldCursor, newCursor);
      var oldPrefix = oldBefore.slice(0, prefixLength);
      var newPrefix = newBefore.slice(0, prefixLength);
      if (oldPrefix !== newPrefix) {
        break editBefore;
      }
      var oldMiddle = oldBefore.slice(prefixLength);
      var newMiddle = newBefore.slice(prefixLength);
      return make_edit_splice(oldPrefix, oldMiddle, newMiddle, oldAfter);
    }
    editAfter: {
      // is this an insert or delete right after oldCursor?
      if (maybeNewCursor !== null && maybeNewCursor !== oldCursor) {
        break editAfter;
      }
      var cursor = oldCursor;
      var newBefore = newText.slice(0, cursor);
      var newAfter = newText.slice(cursor);
      if (newBefore !== oldBefore) {
        break editAfter;
      }
      var suffixLength = Math.min(oldLength - cursor, newLength - cursor);
      var oldSuffix = oldAfter.slice(oldAfter.length - suffixLength);
      var newSuffix = newAfter.slice(newAfter.length - suffixLength);
      if (oldSuffix !== newSuffix) {
        break editAfter;
      }
      var oldMiddle = oldAfter.slice(0, oldAfter.length - suffixLength);
      var newMiddle = newAfter.slice(0, newAfter.length - suffixLength);
      return make_edit_splice(oldBefore, oldMiddle, newMiddle, oldSuffix);
    }
  }
  if (oldRange.length > 0 && newRange && newRange.length === 0) {
    replaceRange: {
      // see if diff could be a splice of the old selection range
      var oldPrefix = oldText.slice(0, oldRange.index);
      var oldSuffix = oldText.slice(oldRange.index + oldRange.length);
      var prefixLength = oldPrefix.length;
      var suffixLength = oldSuffix.length;
      if (newLength < prefixLength + suffixLength) {
        break replaceRange;
      }
      var newPrefix = newText.slice(0, prefixLength);
      var newSuffix = newText.slice(newLength - suffixLength);
      if (oldPrefix !== newPrefix || oldSuffix !== newSuffix) {
        break replaceRange;
      }
      var oldMiddle = oldText.slice(prefixLength, oldLength - suffixLength);
      var newMiddle = newText.slice(prefixLength, newLength - suffixLength);
      return make_edit_splice(oldPrefix, oldMiddle, newMiddle, oldSuffix);
    }
  }

  return null;
}

function diff(text1, text2, cursor_pos, cleanup) {
  // only pass fix_unicode=true at the top level, not when diff_main is
  // recursively invoked
  return diff_main(text1, text2, cursor_pos, cleanup, true);
}

diff.INSERT = DIFF_INSERT;
diff.DELETE = DIFF_DELETE;
diff.EQUAL = DIFF_EQUAL;

module.exports = diff;


fast-diff

description: Fast Javascript text diff

author: Jason Chen <jhchen7@gmail.com>

test: nyc node test.js