Make an observer from a hash of handlers for observation types. This observer can be passed to `observeObject`.
435915
function makeObserver(handlers) {
  console.assert(handlers && typeof handlers === 'object', "Argument to makeObserver must be hash.");
  var handler = assign(create(observerPrototype), handlers);
  var observer = handler.handle.bind(handler);
  observer.keys = getTypesFromHandlers(handlers);
  return observer;
}
398184
function Observer (value) {
  this.value = value;
  this.dep = new Dep();
  this.vmCount = 0;
  def(value, '__ob__', this);
  if (Array.isArray(value)) {
    var augment = hasProto
      ? protoAugment
      : copyAugment;
    augment(value, arrayMethods, arrayKeys);
    this.observeArray(value);
  } else {
    this.walk(value);
  }
}
1132173
def _make_it_so(self, command, calls, *args, **kwargs):
        
        observer = kwargs.pop('observer', False)
        args = (self._fields["hash"],) + args
        try:
            for call in calls:
                self._engine.LOG.debug("%s%s torrent #%s (%s)" % (
                    command[0].upper(), command[1:], self._fields["hash"], call))
                if call.startswith(':') or call[:2].endswith('.'):
                    namespace = self._engine._rpc
                else:
                    namespace = self._engine._rpc.d
                result = getattr(namespace, call.lstrip(':'))(*args)
                if observer:
                    observer(result)
        except xmlrpc.ERRORS as exc:
            raise error.EngineError("While %s torrent #%s: %s" % (command, self._fields["hash"], exc))
1291142
function processObservables (instance) {
  var obs = instance.$observables
  if (obs) {
    return Object.keys(obs).map(key => {
      return {
        type: 'observables',
        key,
        value: instance[key]
      }
    })
  } else {
    return []
  }
}
908689
function observe (value, asRootData) {
  if (!isObject(value) || value instanceof VNode) {
    return
  }
  var ob;
  if (hasOwn(value, '__ob__') && value.__ob__ instanceof Observer) {
    ob = value.__ob__;
  } else if (
    shouldObserve &&
    !isServerRendering() &&
    (Array.isArray(value) || isPlainObject(value)) &&
    Object.isExtensible(value) &&
    !value._isVue
  ) {
    ob = new Observer(value);
  }
  if (asRootData && ob) {
    ob.vmCount++;
  }
  return ob
}
912189
function callObservers(object, chgeset) {
    var ln = object[OBSERVER_PROPERTY];
    if (ln) {
        var elt;
        for (var i = 0, sz = ln.length; sz > i; i++) {
            elt = ln[i];
            if (elt.constructor === Function) {
                elt(chgeset);
            }
        }
    }
}
701519
function createWatchEvent(type, record, event) {
    const payload = Object.assign({ type, key: record.id, modelName: record.modelName, pluralName: record.pluralName, modelConstructor: record.modelConstructor, dynamicPathProperties: record.dynamicPathComponents, compositeKey: record.compositeKey, dbPath: record.dbPath, localPath: record.localPath || "", localPostfix: record.META.localPostfix }, event);
    return payload;
}
357323
def _add_function(self, func, identify_observed):
        

        key = self.make_key(func)
        if key not in self.observers:
            self.observers[key] = ObserverFunction(
                func, identify_observed, (key, self.observers))
            return True
        else:
            return False
917535
function detectObjectObserve() {
    if (typeof Object.observe !== 'function' ||
        typeof Array.observe !== 'function') {
      return false;
    }

    var records = [];

    function callback(recs) {
      records = recs;
    }

    var test = {};
    var arr = [];
    Object.observe(test, callback);
    Array.observe(arr, callback);
    test.id = 1;
    test.id = 2;
    delete test.id;
    arr.push(1, 2);
    arr.length = 0;

    Object.deliverChangeRecords(callback);
    if (records.length !== 5)
      return false;

    if (records[0].type != 'add' ||
        records[1].type != 'update' ||
        records[2].type != 'delete' ||
        records[3].type != 'splice' ||
        records[4].type != 'splice') {
      return false;
    }

    Object.unobserve(test, callback);
    Array.unobserve(arr, callback);

    return true;
  }
789918
def make_key(observer):
        """"""

        if hasattr(observer, "__self__"):
            inst = observer.__self__
            method_name = observer.__name__
            key = (id(inst), method_name)
        else:
            key = id(observer)
        return key
882862
def add_observer(observer_class, func = :handle_event)
      func = func.to_sym

      unless observer_class.instance_methods.include?(func)
        m = "#<#{observer_class}> does not respond to `#{func}'"
        raise NoMethodError, m
      end

      observer_peers[observer_class] = func

      self
    end
52646
function _make(o) {

  var shadow = {};
  var observers = {};
  var actions = {add, update, delete: _delete};

  // Delete a property. Unobserve it, delete shadow and proxy entries.
  function _delete(name) {
    observers[name].unobserve();
    delete observers[name];
    delete u        [name];
    delete shadow   [name];
  }

  // Update a property by reobserving.
  function update(name) {
    observers[name].reobserve(shadow[name]);
  }

  // Add a property. Set up getter and setter, Observe. Populate shadow.
  function add(name) {

    function set(v) {
      var oldValue = shadow[name];
      if (oldValue === v) return;
      o[name] = v;
      notifier.notify({type: 'update', object: u, name, oldValue});
      shadow[name] = oldValue.change(v);
    }

    // When property on upwardable object is accessed, report it and return shadow value.
    function get() {
      accessNotifier.notify({type: 'access', object: u, name});
      return shadow[name];
    }

    function observe(changes) {
//      changes.forEach(change => shadow[name] = shadow[name].change(change.newValue));
//      observers[name].reobserve(shadow[name]);
    }

    shadow[name] = makeUpwardable(o[name]);
    observers[name] = Observer(shadow[name], observe, ['upward']).observe();
    defineProperty(u, name, {set: set, get: get, enumerable: true});
  }

  // Observer to handle new or deleted properties on the object.
  // Pass through to underlying object, which will cause the right things to happen.
  function objectObserver(changes) {
    changes.forEach(({type, name}) => {
      switch (type) {
      case 'add':    o[name] = u[name]; break;
      case 'delete': delete o[name];    break;
      }
    });
  }

  // Observer to handle new, deleted or updated properties on the target.
  function targetObserver(changes) {
    changes.forEach(({type, name}) => actions[type](name));
    //notifier.notify(change); // TODO: figure out what this line was suppsoed to do
  }

  var u = create({}); // null?
  var notifier = getNotifier(u);
  keys(o).forEach(add);
  observe(o, targetObserver);
  observe(u, objectObserver);
  return u;
}
1148564
function makeParamsObserver() {
    
    // Observe and unobserve the children.
    function _observeChildren  (v) { observeObjectNow(v, childrenObserver); }
    function _unobserveChildren(v) { unobserveObject (v, childrenObserver); }
    
    function _observeAttrs(v) {
      observeObjectNow(v, attrsObserver);
      subAttrs.forEach(a => observeObjectNow(v[a], subAttrObservers[a]));
    }
    function _unobserveAttrs(v) {
      unobserveObject(v, AttributesObserver);
      subAttr.forEach(a => unobserveObject(v[a], subAttrObservers[a]));
    }

    // When we get a new parameter, set up observers.
    function add(v, i) {
      switch (i) {
      case 'children':
        _observeChildren(v);
        break;
      case 'attrs':    _observeAttrs   (v); break;
      }
    }
    
    // When parameters change, tear down and resetup observers.
    function update(v, i, params, {oldValue}) {
      switch (i) {
      case 'children': _unobserveChildren(oldValue); _observeChildren(v); break;
      case 'attrs':    _unobserveAttrs   (oldValue); _observeAttrs   (v); break;
      }
    }
    
    return makeObserver({add, update});
  }
328745
def register_observer(self):
        
        self.execution_engine.add_observer(self, "start", notify_before_function=self.on_start)
        self.execution_engine.add_observer(self, "pause", notify_before_function=self.on_pause)
        self.execution_engine.add_observer(self, "stop", notify_before_function=self.on_stop)
107264
def notify_observers(self, event=None, msg=None):
        """"""
        for observer, events in list(self._observers.items()):
            # LOG.debug("trying to notify the observer")
            if events is None or event is None or event in events:
                try:
                    observer(self, event, msg)
                except (Exception,) as ex:  # pylint: disable=broad-except
                    self.unregister_observer(observer)
                    errmsg = "Exception in message dispatch: Handler '{0}' unregistered for event '{1}'  ".format(
                        observer.__class__.__name__, event)
                    LOG.error(errmsg, exc_info=ex)
266081
function observer(name, view) {
	// If no name provided for the observer:
	if (view === undefined) {
		view = name;

		// Generate friendly name for debugging (See: https://github.com/infernojs/inferno/blob/master/packages/inferno-mobx/src/observer.ts#L105)
		name = view.displayName || view.name || (view.constructor && (view.constructor.displayName || view.constructor.name)) || '<View>';
	}

	// The name for the MobX Reaction, for debugging:
	var reactionName = name + ".render()";


	// We need to hook into the init() of the vm, just after that init() is executed,
	// so that all the vm.config(...) have been executed on the vm.
	// This is a bit complex depending on the type of the view.
	// Refer to the ViewModel constructor for details:
	//	 https://github.com/domvm/domvm/blob/3.4.8/src/view/ViewModel.js#L48

	if (isPlainObj(view)) {
		// view is an object: just set our own init on it.
		wrapInit(view, reactionName);
	}
	else {
		// view is a function: we can't do anything before it is executed, so we wrap it
		// with a function that will set our own init later.
		view = (function(view) {
			return function(vm) {
				var out = view.apply(this, arguments);

				if (isFunc(out))
					wrapInit(vm, reactionName);
				else {
					// In case multiple executions of view() returns the same object,
					// we want to wrap init only once:
					wrapInitOnce(out, reactionName);
				}

				return out;
			};
		})(view);
	}

	return view;
}
1228712
function() {
    ElementController.call(this, this.observations);
    this.observersEnabled = false;
    this.listenersEnabled = false;

    if (this.expression && this.updated !== Binding.prototype.updated) {
      // An observer to observe value changes to the expression within a context
      this.observer = this.watch(this.expression, this.updated);
    }
    this.created();
  }