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'use strict';
/**
* DESIGN NOTES
*
* The design decisions behind the scope are heavily favored for speed and memory consumption.
*
* The typical use of scope is to watch the expressions, which most of the time return the same
* value as last time so we optimize the operation.
*
* Closures construction is expensive in terms of speed as well as memory:
* - No closures, instead use prototypical inheritance for API
* - Internal state needs to be stored on scope directly, which means that private state is
* exposed as $$____ properties
*
* Loop operations are optimized by using while(count--) { ... }
* - this means that in order to keep the same order of execution as addition we have to add
* items to the array at the beginning (unshift) instead of at the end (push)
*
* Child scopes are created and removed often
* - Using an array would be slow since inserts in middle are expensive so we use linked list
*
* There are few watches then a lot of observers. This is why you don't want the observer to be
* implemented in the same way as watch. Watch requires return of initialization function which
* are expensive to construct.
*/
/**
* @ngdoc provider
* @name $rootScopeProvider
* @description
*
* Provider for the $rootScope service.
*/
/**
* @ngdoc method
* @name $rootScopeProvider#digestTtl
* @description
*
* Sets the number of `$digest` iterations the scope should attempt to execute before giving up and
* assuming that the model is unstable.
*
* The current default is 10 iterations.
*
* In complex applications it's possible that the dependencies between `$watch`s will result in
* several digest iterations. However if an application needs more than the default 10 digest
* iterations for its model to stabilize then you should investigate what is causing the model to
* continuously change during the digest.
*
* Increasing the TTL could have performance implications, so you should not change it without
* proper justification.
*
* @param {number} limit The number of digest iterations.
*/
/**
* @ngdoc service
* @name $rootScope
* @description
*
* Every application has a single root {@link ng.$rootScope.Scope scope}.
* All other scopes are descendant scopes of the root scope. Scopes provide separation
* between the model and the view, via a mechanism for watching the model for changes.
* They also provide an event emission/broadcast and subscription facility. See the
* {@link guide/scope developer guide on scopes}.
*/
function $RootScopeProvider() {
var TTL = 10;
var $rootScopeMinErr = minErr('$rootScope');
var lastDirtyWatch = null;
var applyAsyncId = null;
this.digestTtl = function(value) {
if (arguments.length) {
TTL = value;
}
return TTL;
};
function createChildScopeClass(parent) {
function ChildScope() {
this.$$watchers = this.$$nextSibling =
this.$$childHead = this.$$childTail = null;
this.$$listeners = {};
this.$$listenerCount = {};
this.$id = nextUid();
this.$$ChildScope = null;
}
ChildScope.prototype = parent;
return ChildScope;
}
this.$get = ['$injector', '$exceptionHandler', '$parse', '$browser',
function($injector, $exceptionHandler, $parse, $browser) {
function destroyChildScope($event) {
$event.currentScope.$$destroyed = true;
}
/**
* @ngdoc type
* @name $rootScope.Scope
*
* @description
* A root scope can be retrieved using the {@link ng.$rootScope $rootScope} key from the
* {@link auto.$injector $injector}. Child scopes are created using the
* {@link ng.$rootScope.Scope#$new $new()} method. (Most scopes are created automatically when
* compiled HTML template is executed.) See also the {@link guide/scope Scopes guide} for
* an in-depth introduction and usage examples.
*
*
* # Inheritance
* A scope can inherit from a parent scope, as in this example:
* ```js
var parent = $rootScope;
var child = parent.$new();
parent.salutation = "Hello";
expect(child.salutation).toEqual('Hello');
child.salutation = "Welcome";
expect(child.salutation).toEqual('Welcome');
expect(parent.salutation).toEqual('Hello');
* ```
*
* When interacting with `Scope` in tests, additional helper methods are available on the
* instances of `Scope` type. See {@link ngMock.$rootScope.Scope ngMock Scope} for additional
* details.
*
*
* @param {Object.<string, function()>=} providers Map of service factory which need to be
* provided for the current scope. Defaults to {@link ng}.
* @param {Object.<string, *>=} instanceCache Provides pre-instantiated services which should
* append/override services provided by `providers`. This is handy
* when unit-testing and having the need to override a default
* service.
* @returns {Object} Newly created scope.
*
*/
function Scope() {
this.$id = nextUid();
this.$$phase = this.$parent = this.$$watchers =
this.$$nextSibling = this.$$prevSibling =
this.$$childHead = this.$$childTail = null;
this.$root = this;
this.$$destroyed = false;
this.$$listeners = {};
this.$$listenerCount = {};
this.$$isolateBindings = null;
}
/**
* @ngdoc property
* @name $rootScope.Scope#$id
*
* @description
* Unique scope ID (monotonically increasing) useful for debugging.
*/
/**
* @ngdoc property
* @name $rootScope.Scope#$parent
*
* @description
* Reference to the parent scope.
*/
/**
* @ngdoc property
* @name $rootScope.Scope#$root
*
* @description
* Reference to the root scope.
*/
Scope.prototype = {
constructor: Scope,
/**
* @ngdoc method
* @name $rootScope.Scope#$new
* @kind function
*
* @description
* Creates a new child {@link ng.$rootScope.Scope scope}.
*
* The parent scope will propagate the {@link ng.$rootScope.Scope#$digest $digest()} event.
* The scope can be removed from the scope hierarchy using {@link ng.$rootScope.Scope#$destroy $destroy()}.
*
* {@link ng.$rootScope.Scope#$destroy $destroy()} must be called on a scope when it is
* desired for the scope and its child scopes to be permanently detached from the parent and
* thus stop participating in model change detection and listener notification by invoking.
*
* @param {boolean} isolate If true, then the scope does not prototypically inherit from the
* parent scope. The scope is isolated, as it can not see parent scope properties.
* When creating widgets, it is useful for the widget to not accidentally read parent
* state.
*
* @param {Scope} [parent=this] The {@link ng.$rootScope.Scope `Scope`} that will be the `$parent`
* of the newly created scope. Defaults to `this` scope if not provided.
* This is used when creating a transclude scope to correctly place it
* in the scope hierarchy while maintaining the correct prototypical
* inheritance.
*
* @returns {Object} The newly created child scope.
*
*/
$new: function(isolate, parent) {
var child;
parent = parent || this;
if (isolate) {
child = new Scope();
child.$root = this.$root;
} else {
// Only create a child scope class if somebody asks for one,
// but cache it to allow the VM to optimize lookups.
if (!this.$$ChildScope) {
this.$$ChildScope = createChildScopeClass(this);
}
child = new this.$$ChildScope();
}
child.$parent = parent;
child.$$prevSibling = parent.$$childTail;
if (parent.$$childHead) {
parent.$$childTail.$$nextSibling = child;
parent.$$childTail = child;
} else {
parent.$$childHead = parent.$$childTail = child;
}
// When the new scope is not isolated or we inherit from `this`, and
// the parent scope is destroyed, the property `$$destroyed` is inherited
// prototypically. In all other cases, this property needs to be set
// when the parent scope is destroyed.
// The listener needs to be added after the parent is set
if (isolate || parent != this) child.$on('$destroy', destroyChildScope);
return child;
},
/**
* @ngdoc method
* @name $rootScope.Scope#$watch
* @kind function
*
* @description
* Registers a `listener` callback to be executed whenever the `watchExpression` changes.
*
* - The `watchExpression` is called on every call to {@link ng.$rootScope.Scope#$digest
* $digest()} and should return the value that will be watched. (Since
* {@link ng.$rootScope.Scope#$digest $digest()} reruns when it detects changes the
* `watchExpression` can execute multiple times per
* {@link ng.$rootScope.Scope#$digest $digest()} and should be idempotent.)
* - The `listener` is called only when the value from the current `watchExpression` and the
* previous call to `watchExpression` are not equal (with the exception of the initial run,
* see below). Inequality is determined according to reference inequality,
* [strict comparison](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Comparison_Operators)
* via the `!==` Javascript operator, unless `objectEquality == true`
* (see next point)
* - When `objectEquality == true`, inequality of the `watchExpression` is determined
* according to the {@link angular.equals} function. To save the value of the object for
* later comparison, the {@link angular.copy} function is used. This therefore means that
* watching complex objects will have adverse memory and performance implications.
* - The watch `listener` may change the model, which may trigger other `listener`s to fire.
* This is achieved by rerunning the watchers until no changes are detected. The rerun
* iteration limit is 10 to prevent an infinite loop deadlock.
*
*
* If you want to be notified whenever {@link ng.$rootScope.Scope#$digest $digest} is called,
* you can register a `watchExpression` function with no `listener`. (Be prepared for
* multiple calls to your `watchExpression` because it will execute multiple times in a
* single {@link ng.$rootScope.Scope#$digest $digest} cycle if a change is detected.)
*
* After a watcher is registered with the scope, the `listener` fn is called asynchronously
* (via {@link ng.$rootScope.Scope#$evalAsync $evalAsync}) to initialize the
* watcher. In rare cases, this is undesirable because the listener is called when the result
* of `watchExpression` didn't change. To detect this scenario within the `listener` fn, you
* can compare the `newVal` and `oldVal`. If these two values are identical (`===`) then the
* listener was called due to initialization.
*
*
*
* # Example
* ```js
// let's assume that scope was dependency injected as the $rootScope
var scope = $rootScope;
scope.name = 'misko';
scope.counter = 0;
expect(scope.counter).toEqual(0);
scope.$watch('name', function(newValue, oldValue) {
scope.counter = scope.counter + 1;
});
expect(scope.counter).toEqual(0);
scope.$digest();
// the listener is always called during the first $digest loop after it was registered
expect(scope.counter).toEqual(1);
scope.$digest();
// but now it will not be called unless the value changes
expect(scope.counter).toEqual(1);
scope.name = 'adam';
scope.$digest();
expect(scope.counter).toEqual(2);
// Using a function as a watchExpression
var food;
scope.foodCounter = 0;
expect(scope.foodCounter).toEqual(0);
scope.$watch(
// This function returns the value being watched. It is called for each turn of the $digest loop
function() { return food; },
// This is the change listener, called when the value returned from the above function changes
function(newValue, oldValue) {
if ( newValue !== oldValue ) {
// Only increment the counter if the value changed
scope.foodCounter = scope.foodCounter + 1;
}
}
);
// No digest has been run so the counter will be zero
expect(scope.foodCounter).toEqual(0);
// Run the digest but since food has not changed count will still be zero
scope.$digest();
expect(scope.foodCounter).toEqual(0);
// Update food and run digest. Now the counter will increment
food = 'cheeseburger';
scope.$digest();
expect(scope.foodCounter).toEqual(1);
* ```
*
*
*
* @param {(function()|string)} watchExpression Expression that is evaluated on each
* {@link ng.$rootScope.Scope#$digest $digest} cycle. A change in the return value triggers
* a call to the `listener`.
*
* - `string`: Evaluated as {@link guide/expression expression}
* - `function(scope)`: called with current `scope` as a parameter.
* @param {function(newVal, oldVal, scope)} listener Callback called whenever the value
* of `watchExpression` changes.
*
* - `newVal` contains the current value of the `watchExpression`
* - `oldVal` contains the previous value of the `watchExpression`
* - `scope` refers to the current scope
* @param {boolean=} objectEquality Compare for object equality using {@link angular.equals} instead of
* comparing for reference equality.
* @returns {function()} Returns a deregistration function for this listener.
*/
$watch: function(watchExp, listener, objectEquality) {
var get = $parse(watchExp);
if (get.$$watchDelegate) {
return get.$$watchDelegate(this, listener, objectEquality, get);
}
var scope = this,
array = scope.$$watchers,
watcher = {
fn: listener,
last: initWatchVal,
get: get,
exp: watchExp,
eq: !!objectEquality
};
lastDirtyWatch = null;
if (!isFunction(listener)) {
watcher.fn = noop;
}
if (!array) {
array = scope.$$watchers = [];
}
// we use unshift since we use a while loop in $digest for speed.
// the while loop reads in reverse order.
array.unshift(watcher);
return function deregisterWatch() {
arrayRemove(array, watcher);
lastDirtyWatch = null;
};
},
/**
* @ngdoc method
* @name $rootScope.Scope#$watchGroup
* @kind function
*
* @description
* A variant of {@link ng.$rootScope.Scope#$watch $watch()} where it watches an array of `watchExpressions`.
* If any one expression in the collection changes the `listener` is executed.
*
* - The items in the `watchExpressions` array are observed via standard $watch operation and are examined on every
* call to $digest() to see if any items changes.
* - The `listener` is called whenever any expression in the `watchExpressions` array changes.
*
* @param {Array.<string|Function(scope)>} watchExpressions Array of expressions that will be individually
* watched using {@link ng.$rootScope.Scope#$watch $watch()}
*
* @param {function(newValues, oldValues, scope)} listener Callback called whenever the return value of any
* expression in `watchExpressions` changes
* The `newValues` array contains the current values of the `watchExpressions`, with the indexes matching
* those of `watchExpression`
* and the `oldValues` array contains the previous values of the `watchExpressions`, with the indexes matching
* those of `watchExpression`
* The `scope` refers to the current scope.
* @returns {function()} Returns a de-registration function for all listeners.
*/
$watchGroup: function(watchExpressions, listener) {
var oldValues = new Array(watchExpressions.length);
var newValues = new Array(watchExpressions.length);
var deregisterFns = [];
var self = this;
var changeReactionScheduled = false;
var firstRun = true;
if (!watchExpressions.length) {
// No expressions means we call the listener ASAP
var shouldCall = true;
self.$evalAsync(function() {
if (shouldCall) listener(newValues, newValues, self);
});
return function deregisterWatchGroup() {
shouldCall = false;
};
}
if (watchExpressions.length === 1) {
// Special case size of one
return this.$watch(watchExpressions[0], function watchGroupAction(value, oldValue, scope) {
newValues[0] = value;
oldValues[0] = oldValue;
listener(newValues, (value === oldValue) ? newValues : oldValues, scope);
});
}
forEach(watchExpressions, function(expr, i) {
var unwatchFn = self.$watch(expr, function watchGroupSubAction(value, oldValue) {
newValues[i] = value;
oldValues[i] = oldValue;
if (!changeReactionScheduled) {
changeReactionScheduled = true;
self.$evalAsync(watchGroupAction);
}
});
deregisterFns.push(unwatchFn);
});
function watchGroupAction() {
changeReactionScheduled = false;
if (firstRun) {
firstRun = false;
listener(newValues, newValues, self);
} else {
listener(newValues, oldValues, self);
}
}
return function deregisterWatchGroup() {
while (deregisterFns.length) {
deregisterFns.shift()();
}
};
},
/**
* @ngdoc method
* @name $rootScope.Scope#$watchCollection
* @kind function
*
* @description
* Shallow watches the properties of an object and fires whenever any of the properties change
* (for arrays, this implies watching the array items; for object maps, this implies watching
* the properties). If a change is detected, the `listener` callback is fired.
*
* - The `obj` collection is observed via standard $watch operation and is examined on every
* call to $digest() to see if any items have been added, removed, or moved.
* - The `listener` is called whenever anything within the `obj` has changed. Examples include
* adding, removing, and moving items belonging to an object or array.
*
*
* # Example
* ```js
$scope.names = ['igor', 'matias', 'misko', 'james'];
$scope.dataCount = 4;
$scope.$watchCollection('names', function(newNames, oldNames) {
$scope.dataCount = newNames.length;
});
expect($scope.dataCount).toEqual(4);
$scope.$digest();
//still at 4 ... no changes
expect($scope.dataCount).toEqual(4);
$scope.names.pop();
$scope.$digest();
//now there's been a change
expect($scope.dataCount).toEqual(3);
* ```
*
*
* @param {string|function(scope)} obj Evaluated as {@link guide/expression expression}. The
* expression value should evaluate to an object or an array which is observed on each
* {@link ng.$rootScope.Scope#$digest $digest} cycle. Any shallow change within the
* collection will trigger a call to the `listener`.
*
* @param {function(newCollection, oldCollection, scope)} listener a callback function called
* when a change is detected.
* - The `newCollection` object is the newly modified data obtained from the `obj` expression
* - The `oldCollection` object is a copy of the former collection data.
* Due to performance considerations, the`oldCollection` value is computed only if the
* `listener` function declares two or more arguments.
* - The `scope` argument refers to the current scope.
*
* @returns {function()} Returns a de-registration function for this listener. When the
* de-registration function is executed, the internal watch operation is terminated.
*/
$watchCollection: function(obj, listener) {
$watchCollectionInterceptor.$stateful = true;
var self = this;
// the current value, updated on each dirty-check run
var newValue;
// a shallow copy of the newValue from the last dirty-check run,
// updated to match newValue during dirty-check run
var oldValue;
// a shallow copy of the newValue from when the last change happened
var veryOldValue;
// only track veryOldValue if the listener is asking for it
var trackVeryOldValue = (listener.length > 1);
var changeDetected = 0;
var changeDetector = $parse(obj, $watchCollectionInterceptor);
var internalArray = [];
var internalObject = {};
var initRun = true;
var oldLength = 0;
function $watchCollectionInterceptor(_value) {
newValue = _value;
var newLength, key, bothNaN, newItem, oldItem;
// If the new value is undefined, then return undefined as the watch may be a one-time watch
if (isUndefined(newValue)) return;
if (!isObject(newValue)) { // if primitive
if (oldValue !== newValue) {
oldValue = newValue;
changeDetected++;
}
} else if (isArrayLike(newValue)) {
if (oldValue !== internalArray) {
// we are transitioning from something which was not an array into array.
oldValue = internalArray;
oldLength = oldValue.length = 0;
changeDetected++;
}
newLength = newValue.length;
if (oldLength !== newLength) {
// if lengths do not match we need to trigger change notification
changeDetected++;
oldValue.length = oldLength = newLength;
}
// copy the items to oldValue and look for changes.
for (var i = 0; i < newLength; i++) {
oldItem = oldValue[i];
newItem = newValue[i];
bothNaN = (oldItem !== oldItem) && (newItem !== newItem);
if (!bothNaN && (oldItem !== newItem)) {
changeDetected++;
oldValue[i] = newItem;
}
}
} else {
if (oldValue !== internalObject) {
// we are transitioning from something which was not an object into object.
oldValue = internalObject = {};
oldLength = 0;
changeDetected++;
}
// copy the items to oldValue and look for changes.
newLength = 0;
for (key in newValue) {
if (newValue.hasOwnProperty(key)) {
newLength++;
newItem = newValue[key];
oldItem = oldValue[key];
if (key in oldValue) {
bothNaN = (oldItem !== oldItem) && (newItem !== newItem);
if (!bothNaN && (oldItem !== newItem)) {
changeDetected++;
oldValue[key] = newItem;
}
} else {
oldLength++;
oldValue[key] = newItem;
changeDetected++;
}
}
}
if (oldLength > newLength) {
// we used to have more keys, need to find them and destroy them.
changeDetected++;
for (key in oldValue) {
if (!newValue.hasOwnProperty(key)) {
oldLength--;
delete oldValue[key];
}
}
}
}
return changeDetected;
}
function $watchCollectionAction() {
if (initRun) {
initRun = false;
listener(newValue, newValue, self);
} else {
listener(newValue, veryOldValue, self);
}
// make a copy for the next time a collection is changed
if (trackVeryOldValue) {
if (!isObject(newValue)) {
//primitive
veryOldValue = newValue;
} else if (isArrayLike(newValue)) {
veryOldValue = new Array(newValue.length);
for (var i = 0; i < newValue.length; i++) {
veryOldValue[i] = newValue[i];
}
} else { // if object
veryOldValue = {};
for (var key in newValue) {
if (hasOwnProperty.call(newValue, key)) {
veryOldValue[key] = newValue[key];
}
}
}
}
}
return this.$watch(changeDetector, $watchCollectionAction);
},
/**
* @ngdoc method
* @name $rootScope.Scope#$digest
* @kind function
*
* @description
* Processes all of the {@link ng.$rootScope.Scope#$watch watchers} of the current scope and
* its children. Because a {@link ng.$rootScope.Scope#$watch watcher}'s listener can change
* the model, the `$digest()` keeps calling the {@link ng.$rootScope.Scope#$watch watchers}
* until no more listeners are firing. This means that it is possible to get into an infinite
* loop. This function will throw `'Maximum iteration limit exceeded.'` if the number of
* iterations exceeds 10.
*
* Usually, you don't call `$digest()` directly in
* {@link ng.directive:ngController controllers} or in
* {@link ng.$compileProvider#directive directives}.
* Instead, you should call {@link ng.$rootScope.Scope#$apply $apply()} (typically from within
* a {@link ng.$compileProvider#directive directive}), which will force a `$digest()`.
*
* If you want to be notified whenever `$digest()` is called,
* you can register a `watchExpression` function with
* {@link ng.$rootScope.Scope#$watch $watch()} with no `listener`.
*
* In unit tests, you may need to call `$digest()` to simulate the scope life cycle.
*
* # Example
* ```js
var scope = ...;
scope.name = 'misko';
scope.counter = 0;
expect(scope.counter).toEqual(0);
scope.$watch('name', function(newValue, oldValue) {
scope.counter = scope.counter + 1;
});
expect(scope.counter).toEqual(0);
scope.$digest();
// the listener is always called during the first $digest loop after it was registered
expect(scope.counter).toEqual(1);
scope.$digest();
// but now it will not be called unless the value changes
expect(scope.counter).toEqual(1);
scope.name = 'adam';
scope.$digest();
expect(scope.counter).toEqual(2);
* ```
*
*/
$digest: function() {
var watch, value, last,
watchers,
length,
dirty, ttl = TTL,
next, current, target = this,
watchLog = [],
logIdx, logMsg, asyncTask;
beginPhase('$digest');
// Check for changes to browser url that happened in sync before the call to $digest
$browser.$$checkUrlChange();
if (this === $rootScope && applyAsyncId !== null) {
// If this is the root scope, and $applyAsync has scheduled a deferred $apply(), then
// cancel the scheduled $apply and flush the queue of expressions to be evaluated.
$browser.defer.cancel(applyAsyncId);
flushApplyAsync();
}
lastDirtyWatch = null;
do { // "while dirty" loop
dirty = false;
current = target;
while (asyncQueue.length) {
try {
asyncTask = asyncQueue.shift();
asyncTask.scope.$eval(asyncTask.expression, asyncTask.locals);
} catch (e) {
$exceptionHandler(e);
}
lastDirtyWatch = null;
}
traverseScopesLoop:
do { // "traverse the scopes" loop
if ((watchers = current.$$watchers)) {
// process our watches
length = watchers.length;
while (length--) {
try {
watch = watchers[length];
// Most common watches are on primitives, in which case we can short
// circuit it with === operator, only when === fails do we use .equals
if (watch) {
if ((value = watch.get(current)) !== (last = watch.last) &&
!(watch.eq
? equals(value, last)
: (typeof value === 'number' && typeof last === 'number'
&& isNaN(value) && isNaN(last)))) {
dirty = true;
lastDirtyWatch = watch;
watch.last = watch.eq ? copy(value, null) : value;
watch.fn(value, ((last === initWatchVal) ? value : last), current);
if (ttl < 5) {
logIdx = 4 - ttl;
if (!watchLog[logIdx]) watchLog[logIdx] = [];
watchLog[logIdx].push({
msg: isFunction(watch.exp) ? 'fn: ' + (watch.exp.name || watch.exp.toString()) : watch.exp,
newVal: value,
oldVal: last
});
}
} else if (watch === lastDirtyWatch) {
// If the most recently dirty watcher is now clean, short circuit since the remaining watchers
// have already been tested.
dirty = false;
break traverseScopesLoop;
}
}
} catch (e) {
$exceptionHandler(e);
}
}
}
// Insanity Warning: scope depth-first traversal
// yes, this code is a bit crazy, but it works and we have tests to prove it!
// this piece should be kept in sync with the traversal in $broadcast
if (!(next = (current.$$childHead ||
(current !== target && current.$$nextSibling)))) {
while (current !== target && !(next = current.$$nextSibling)) {
current = current.$parent;
}
}
} while ((current = next));
// `break traverseScopesLoop;` takes us to here
if ((dirty || asyncQueue.length) && !(ttl--)) {
clearPhase();
throw $rootScopeMinErr('infdig',
'{0} $digest() iterations reached. Aborting!\n' +
'Watchers fired in the last 5 iterations: {1}',
TTL, watchLog);
}
} while (dirty || asyncQueue.length);
clearPhase();
while (postDigestQueue.length) {
try {
postDigestQueue.shift()();
} catch (e) {
$exceptionHandler(e);
}
}
},
/**
* @ngdoc event
* @name $rootScope.Scope#$destroy
* @eventType broadcast on scope being destroyed
*
* @description
* Broadcasted when a scope and its children are being destroyed.
*
* Note that, in AngularJS, there is also a `$destroy` jQuery event, which can be used to
* clean up DOM bindings before an element is removed from the DOM.
*/
/**
* @ngdoc method
* @name $rootScope.Scope#$destroy
* @kind function
*
* @description
* Removes the current scope (and all of its children) from the parent scope. Removal implies
* that calls to {@link ng.$rootScope.Scope#$digest $digest()} will no longer
* propagate to the current scope and its children. Removal also implies that the current
* scope is eligible for garbage collection.
*
* The `$destroy()` is usually used by directives such as
* {@link ng.directive:ngRepeat ngRepeat} for managing the
* unrolling of the loop.
*
* Just before a scope is destroyed, a `$destroy` event is broadcasted on this scope.
* Application code can register a `$destroy` event handler that will give it a chance to
* perform any necessary cleanup.
*
* Note that, in AngularJS, there is also a `$destroy` jQuery event, which can be used to
* clean up DOM bindings before an element is removed from the DOM.
*/
$destroy: function() {
// we can't destroy the root scope or a scope that has been already destroyed
if (this.$$destroyed) return;
var parent = this.$parent;
this.$broadcast('$destroy');
this.$$destroyed = true;
if (this === $rootScope) return;
for (var eventName in this.$$listenerCount) {
decrementListenerCount(this, this.$$listenerCount[eventName], eventName);
}
// sever all the references to parent scopes (after this cleanup, the current scope should
// not be retained by any of our references and should be eligible for garbage collection)
if (parent.$$childHead == this) parent.$$childHead = this.$$nextSibling;
if (parent.$$childTail == this) parent.$$childTail = this.$$prevSibling;
if (this.$$prevSibling) this.$$prevSibling.$$nextSibling = this.$$nextSibling;
if (this.$$nextSibling) this.$$nextSibling.$$prevSibling = this.$$prevSibling;
// Disable listeners, watchers and apply/digest methods
this.$destroy = this.$digest = this.$apply = this.$evalAsync = this.$applyAsync = noop;
this.$on = this.$watch = this.$watchGroup = function() { return noop; };
this.$$listeners = {};
// All of the code below is bogus code that works around V8's memory leak via optimized code
// and inline caches.
//
// see:
// - https://code.google.com/p/v8/issues/detail?id=2073#c26
// - https://github.com/angular/angular.js/issues/6794#issuecomment-38648909
// - https://github.com/angular/angular.js/issues/1313#issuecomment-10378451
this.$parent = this.$$nextSibling = this.$$prevSibling = this.$$childHead =
this.$$childTail = this.$root = this.$$watchers = null;
},
/**
* @ngdoc method
* @name $rootScope.Scope#$eval
* @kind function
*
* @description
* Executes the `expression` on the current scope and returns the result. Any exceptions in
* the expression are propagated (uncaught). This is useful when evaluating Angular
* expressions.
*
* # Example
* ```js
var scope = ng.$rootScope.Scope();
scope.a = 1;
scope.b = 2;
expect(scope.$eval('a+b')).toEqual(3);
expect(scope.$eval(function(scope){ return scope.a + scope.b; })).toEqual(3);
* ```
*
* @param {(string|function())=} expression An angular expression to be executed.
*
* - `string`: execute using the rules as defined in {@link guide/expression expression}.
* - `function(scope)`: execute the function with the current `scope` parameter.
*
* @param {(object)=} locals Local variables object, useful for overriding values in scope.
* @returns {*} The result of evaluating the expression.
*/
$eval: function(expr, locals) {
return $parse(expr)(this, locals);
},
/**
* @ngdoc method
* @name $rootScope.Scope#$evalAsync
* @kind function
*
* @description
* Executes the expression on the current scope at a later point in time.
*
* The `$evalAsync` makes no guarantees as to when the `expression` will be executed, only
* that:
*
* - it will execute after the function that scheduled the evaluation (preferably before DOM
* rendering).
* - at least one {@link ng.$rootScope.Scope#$digest $digest cycle} will be performed after
* `expression` execution.
*
* Any exceptions from the execution of the expression are forwarded to the
* {@link ng.$exceptionHandler $exceptionHandler} service.
*
* __Note:__ if this function is called outside of a `$digest` cycle, a new `$digest` cycle
* will be scheduled. However, it is encouraged to always call code that changes the model
* from within an `$apply` call. That includes code evaluated via `$evalAsync`.
*
* @param {(string|function())=} expression An angular expression to be executed.
*
* - `string`: execute using the rules as defined in {@link guide/expression expression}.
* - `function(scope)`: execute the function with the current `scope` parameter.
*
* @param {(object)=} locals Local variables object, useful for overriding values in scope.
*/
$evalAsync: function(expr, locals) {
// if we are outside of an $digest loop and this is the first time we are scheduling async
// task also schedule async auto-flush
if (!$rootScope.$$phase && !asyncQueue.length) {
$browser.defer(function() {
if (asyncQueue.length) {
$rootScope.$digest();
}
});
}
asyncQueue.push({scope: this, expression: expr, locals: locals});
},
$$postDigest: function(fn) {
postDigestQueue.push(fn);
},
/**
* @ngdoc method
* @name $rootScope.Scope#$apply
* @kind function
*
* @description
* `$apply()` is used to execute an expression in angular from outside of the angular
* framework. (For example from browser DOM events, setTimeout, XHR or third party libraries).
* Because we are calling into the angular framework we need to perform proper scope life
* cycle of {@link ng.$exceptionHandler exception handling},
* {@link ng.$rootScope.Scope#$digest executing watches}.
*
* ## Life cycle
*
* # Pseudo-Code of `$apply()`
* ```js
function $apply(expr) {
try {
return $eval(expr);