Ember.ArrayProxy Class packages/ember-runtime/lib/system/array_proxy.js:36
PUBLIC
Extends: Ember.Object
Uses: Ember.MutableArray
Defined in: packages/ember-runtime/lib/system/array_proxy.js:36
Module: ember-runtime
An ArrayProxy wraps any other object that implements Ember.Array
and/or
Ember.MutableArray,
forwarding all requests. This makes it very useful for
a number of binding use cases or other cases where being able to swap
out the underlying array is useful.
A simple example of usage:
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var pets = ['dog', 'cat', 'fish']; var ap = Ember.ArrayProxy.create({ content: Ember.A(pets) }); ap.get('firstObject'); // 'dog' ap.set('content', ['amoeba', 'paramecium']); ap.get('firstObject'); // 'amoeba' |
This class can also be useful as a layer to transform the contents of
an array, as they are accessed. This can be done by overriding
objectAtContent
:
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var pets = ['dog', 'cat', 'fish']; var ap = Ember.ArrayProxy.create({ content: Ember.A(pets), objectAtContent: function(idx) { return this.get('content').objectAt(idx).toUpperCase(); } }); ap.get('firstObject'); // . 'DOG' |
Methods
- _contentDidChange
- _contentWillChange
- _lazyInjections
- _onLookup
- _scheduledDestroy
- addArrayObserver
- addEnumerableObserver
- addObject
- addObjects
- addObserver
- any
- arrayContentDidChange
- arrayContentWillChange
- beginPropertyChanges
- cacheFor
- clear
- compact
- contains
- contentArrayDidChange
- contentArrayWillChange
- create
- decrementProperty
- destroy
- eachComputedProperty
- endPropertyChanges
- enumerableContentDidChange
- enumerableContentWillChange
- every
- extend
- filter
- filterBy
- find
- findBy
- forEach
- get
- getEach
- getProperties
- getWithDefault
- hasObserverFor
- incrementProperty
- indexOf
- init
- insertAt
- invoke
- isAny
- isEvery
- lastIndexOf
- map
- mapBy
- metaForProperty
- nextObject
- notifyPropertyChange
- objectAt
- objectAtContent
- objectsAt
- popObject
- propertyDidChange
- propertyWillChange
- pushObject
- pushObjects
- reduce
- reject
- rejectBy
- removeArrayObserver
- removeAt
- removeEnumerableObserver
- removeObject
- removeObjects
- removeObserver
- reopen
- reopenClass
- replace
- replaceContent
- reverseObjects
- set
- setEach
- setObjects
- setProperties
- shiftObject
- slice
- sortBy
- toArray
- toString
- toggleProperty
- uniq
- unshiftObject
- unshiftObjects
- willDestroy
- without
Properties
_contentDidChange
private
Invoked when the content property changes. Notifies observers that the entire array content has changed.
_contentWillChange
private
Invoked when the content property is about to change. Notifies observers that the entire array content will change.
_lazyInjections
Object
private
Returns a hash of property names and container names that injected properties will lookup on the container lazily.
Returns:
- Object
- Hash of all lazy injected property keys to container names
_onLookup
private
Provides lookup-time type validation for injected properties.
_scheduledDestroy
private
Invoked by the run loop to actually destroy the object. This is
scheduled for execution by the destroy
method.
addArrayObserver
(target, opts)
Ember.Array
public
Adds an array observer to the receiving array. The array observer object normally must implement two methods:
arrayWillChange(observedObj, start, removeCount, addCount)
- This method will be called just before the array is modified.arrayDidChange(observedObj, start, removeCount, addCount)
- This method will be called just after the array is modified.
Both callbacks will be passed the observed object, starting index of the change as well as a count of the items to be removed and added. You can use these callbacks to optionally inspect the array during the change, clear caches, or do any other bookkeeping necessary.
In addition to passing a target, you can also include an options hash which you can use to override the method names that will be invoked on the target.
Parameters:
- target Object
- The observer object.
- opts Object
- Optional hash of configuration options including `willChange` and `didChange` option.
Returns:
- Ember.Array
- receiver
addEnumerableObserver
(target, opts)
private
Registers an enumerable observer. Must implement Ember.EnumerableObserver
mixin.
Parameters:
- target Object
- opts [Object]
Returns:
- this
addObject
(obj)
Ember.Array
public
Push the object onto the end of the array if it is not already present in the array.
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var cities = ['Chicago', 'Berlin']; cities.addObject('Lima'); // ['Chicago', 'Berlin', 'Lima'] cities.addObject('Berlin'); // ['Chicago', 'Berlin', 'Lima'] |
Parameters:
- obj *
- object to add, if not already present
Returns:
- Ember.Array
- receiver
addObjects
(objects)
Object
public
Adds each object in the passed enumerable to the receiver.
Parameters:
- objects Ember.Enumerable
- the objects to add.
Returns:
- Object
- receiver
addObserver
(key, target, method)
public
Adds an observer on a property.
This is the core method used to register an observer for a property.
Once you call this method, any time the key's value is set, your observer will be notified. Note that the observers are triggered any time the value is set, regardless of whether it has actually changed. Your observer should be prepared to handle that.
You can also pass an optional context parameter to this method. The context will be passed to your observer method whenever it is triggered. Note that if you add the same target/method pair on a key multiple times with different context parameters, your observer will only be called once with the last context you passed.
Observer Methods
Observer methods you pass should generally have the following signature if
you do not pass a context
parameter:
1 |
fooDidChange: function(sender, key, value, rev) { }; |
The sender is the object that changed. The key is the property that changes. The value property is currently reserved and unused. The rev is the last property revision of the object when it changed, which you can use to detect if the key value has really changed or not.
If you pass a context
parameter, the context will be passed before the
revision like so:
1 |
fooDidChange: function(sender, key, value, context, rev) { }; |
Usually you will not need the value, context or revision parameters at the end. In this case, it is common to write observer methods that take only a sender and key value as parameters or, if you aren't interested in any of these values, to write an observer that has no parameters at all.
Parameters:
- key String
- The key to observer
- target Object
- The target object to invoke
- method String|Function
- The method to invoke.
any
(callback, target)
Boolean
public
Returns true
if the passed function returns true for any item in the
enumeration. This corresponds with the some()
method in JavaScript 1.6.
The callback method you provide should have the following signature (all parameters are optional):
1 |
function(item, index, enumerable);
|
item
is the current item in the iteration.index
is the current index in the iteration.enumerable
is the enumerable object itself.
It should return the true
to include the item in the results, false
otherwise.
Note that in addition to a callback, you can also pass an optional target
object that will be set as this
on the context. This is a good way
to give your iterator function access to the current object.
Usage Example:
1 2 3 |
if (people.any(isManager)) {
Paychecks.addBiggerBonus();
}
|
Parameters:
- callback Function
- The callback to execute
- target [Object]
- The target object to use
Returns:
- Boolean
- `true` if the passed function returns `true` for any item
arrayContentDidChange
(startIdx, removeAmt, addAmt)
Ember.Array
public
If you are implementing an object that supports Ember.Array
, call this
method just after the array content changes to notify any observers and
invalidate any related properties. Pass the starting index of the change
as well as a delta of the amounts to change.
Parameters:
- startIdx Number
- The starting index in the array that did change.
- removeAmt Number
- The number of items that were removed. If you pass `null` assumes 0
- addAmt Number
- The number of items that were added. If you pass `null` assumes 0.
Returns:
- Ember.Array
- receiver
arrayContentWillChange
(startIdx, removeAmt, addAmt)
Ember.Array
public
If you are implementing an object that supports Ember.Array
, call this
method just before the array content changes to notify any observers and
invalidate any related properties. Pass the starting index of the change
as well as a delta of the amounts to change.
Parameters:
- startIdx Number
- The starting index in the array that will change.
- removeAmt Number
- The number of items that will be removed. If you pass `null` assumes 0
- addAmt Number
- The number of items that will be added. If you pass `null` assumes 0.
Returns:
- Ember.Array
- receiver
beginPropertyChanges
Ember.Observable
private
Begins a grouping of property changes.
You can use this method to group property changes so that notifications
will not be sent until the changes are finished. If you plan to make a
large number of changes to an object at one time, you should call this
method at the beginning of the changes to begin deferring change
notifications. When you are done making changes, call
endPropertyChanges()
to deliver the deferred change notifications and end
deferring.
Returns:
cacheFor
(keyName)
Object
public
Returns the cached value of a computed property, if it exists. This allows you to inspect the value of a computed property without accidentally invoking it if it is intended to be generated lazily.
Parameters:
- keyName String
Returns:
- Object
- The cached value of the computed property, if any
clear
Ember.Array
public
Remove all elements from the array. This is useful if you want to reuse an existing array without having to recreate it.
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var colors = ['red', 'green', 'blue']; color.length(); // 3 colors.clear(); // [] colors.length(); // 0 |
Returns:
- Ember.Array
- An empty Array.
compact
Array
public
Returns a copy of the array with all null
and undefined
elements removed.
1 2 |
var arr = ['a', null, 'c', undefined]; arr.compact(); // ['a', 'c'] |
Returns:
- Array
- the array without null and undefined elements.
contains
(obj)
Boolean
public
Returns true
if the passed object can be found in the receiver. The
default version will iterate through the enumerable until the object
is found. You may want to override this with a more efficient version.
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var arr = ['a', 'b', 'c']; arr.contains('a'); // true arr.contains('z'); // false |
Parameters:
- obj Object
- The object to search for.
Returns:
- Boolean
- `true` if object is found in enumerable.
contentArrayDidChange
(contentArray, start, removeCount, addCount)
private
Override to implement content array didChange
observer.
Parameters:
- contentArray Ember.Array
- the content array
- start Number
- starting index of the change
- removeCount Number
- count of items removed
- addCount Number
- count of items added
contentArrayWillChange
(contentArray, start, removeCount, addCount)
private
Override to implement content array willChange
observer.
Parameters:
- contentArray Ember.Array
- the content array
- start Number
- starting index of the change
- removeCount Number
- count of items removed
- addCount Number
- count of items added
create
(arguments)
public
static
Creates an instance of a class. Accepts either no arguments, or an object containing values to initialize the newly instantiated object with.
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App.Person = Ember.Object.extend({ helloWorld: function() { alert("Hi, my name is " + this.get('name')); } }); var tom = App.Person.create({ name: 'Tom Dale' }); tom.helloWorld(); // alerts "Hi, my name is Tom Dale". |
create
will call the init
function if defined during
Ember.AnyObject.extend
If no arguments are passed to create
, it will not set values to the new
instance during initialization:
1 2 |
var noName = App.Person.create(); noName.helloWorld(); // alerts undefined |
NOTE: For performance reasons, you cannot declare methods or computed
properties during create
. You should instead declare methods and computed
properties when using extend
.
Parameters:
- arguments []
decrementProperty
(keyName, decrement)
Number
public
Set the value of a property to the current value minus some amount.
1 2 |
player.decrementProperty('lives'); orc.decrementProperty('health', 5); |
Parameters:
- keyName String
- The name of the property to decrement
- decrement Number
- The amount to decrement by. Defaults to 1
Returns:
- Number
- The new property value
destroy
Ember.Object
public
Destroys an object by setting the isDestroyed
flag and removing its
metadata, which effectively destroys observers and bindings.
If you try to set a property on a destroyed object, an exception will be raised.
Note that destruction is scheduled for the end of the run loop and does not happen immediately. It will set an isDestroying flag immediately.
Returns:
- Ember.Object
- receiver
eachComputedProperty
(callback, binding)
private
static
Iterate over each computed property for the class, passing its name
and any associated metadata (see metaForProperty
) to the callback.
Parameters:
- callback Function
- binding Object
endPropertyChanges
Ember.Observable
private
Ends a grouping of property changes.
You can use this method to group property changes so that notifications
will not be sent until the changes are finished. If you plan to make a
large number of changes to an object at one time, you should call
beginPropertyChanges()
at the beginning of the changes to defer change
notifications. When you are done making changes, call this method to
deliver the deferred change notifications and end deferring.
Returns:
enumerableContentDidChange
(removing, adding)
private
Invoke this method when the contents of your enumerable has changed. This will notify any observers watching for content changes. If you are implementing an ordered enumerable (such as an array), also pass the start and end values where the content changed so that it can be used to notify range observers.
Parameters:
- removing Ember.Enumerable|Number
- An enumerable of the objects to be removed or the number of items to be removed.
- adding Ember.Enumerable|Number
- An enumerable of the objects to be added or the number of items to be added.
enumerableContentWillChange
(removing, adding)
private
Invoke this method just before the contents of your enumerable will change. You can either omit the parameters completely or pass the objects to be removed or added if available or just a count.
Parameters:
- removing Ember.Enumerable|Number
- An enumerable of the objects to be removed or the number of items to be removed.
- adding Ember.Enumerable|Number
- An enumerable of the objects to be added or the number of items to be added.
every
(callback, target)
Boolean
public
Returns true
if the passed function returns true for every item in the
enumeration. This corresponds with the every()
method in JavaScript 1.6.
The callback method you provide should have the following signature (all parameters are optional):
1 |
function(item, index, enumerable);
|
item
is the current item in the iteration.index
is the current index in the iteration.enumerable
is the enumerable object itself.
It should return the true
or false
.
Note that in addition to a callback, you can also pass an optional target
object that will be set as this
on the context. This is a good way
to give your iterator function access to the current object.
Example Usage:
1 2 3 |
if (people.every(isEngineer)) {
Paychecks.addBigBonus();
}
|
Parameters:
- callback Function
- The callback to execute
- target [Object]
- The target object to use
Returns:
- Boolean
extend
(mixins, arguments)
public
static
Creates a new subclass.
1 2 3 4 5 |
App.Person = Ember.Object.extend({ say: function(thing) { alert(thing); } }); |
This defines a new subclass of Ember.Object: App.Person
. It contains one method: say()
.
You can also create a subclass from any existing class by calling its extend()
method.
For example, you might want to create a subclass of Ember's built-in Ember.View
class:
1 2 3 4 |
App.PersonView = Ember.View.extend({ tagName: 'li', classNameBindings: ['isAdministrator'] }); |
When defining a subclass, you can override methods but still access the
implementation of your parent class by calling the special _super()
method:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 |
App.Person = Ember.Object.extend({ say: function(thing) { var name = this.get('name'); alert(name + ' says: ' + thing); } }); App.Soldier = App.Person.extend({ say: function(thing) { this._super(thing + ", sir!"); }, march: function(numberOfHours) { alert(this.get('name') + ' marches for ' + numberOfHours + ' hours.'); } }); var yehuda = App.Soldier.create({ name: "Yehuda Katz" }); yehuda.say("Yes"); // alerts "Yehuda Katz says: Yes, sir!" |
The create()
on line #17 creates an instance of the App.Soldier
class.
The extend()
on line #8 creates a subclass of App.Person
. Any instance
of the App.Person
class will not have the march()
method.
You can also pass Mixin
classes to add additional properties to the subclass.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 |
App.Person = Ember.Object.extend({ say: function(thing) { alert(this.get('name') + ' says: ' + thing); } }); App.SingingMixin = Mixin.create({ sing: function(thing){ alert(this.get('name') + ' sings: la la la ' + thing); } }); App.BroadwayStar = App.Person.extend(App.SingingMixin, { dance: function() { alert(this.get('name') + ' dances: tap tap tap tap '); } }); |
The App.BroadwayStar
class contains three methods: say()
, sing()
, and dance()
.
Parameters:
- mixins [Mixin]
- One or more Mixin classes
- arguments [Object]
- Object containing values to use within the new class
filter
(callback, target)
Array
public
Returns an array with all of the items in the enumeration that the passed
function returns true for. This method corresponds to filter()
defined in
JavaScript 1.6.
The callback method you provide should have the following signature (all parameters are optional):
1 |
function(item, index, enumerable);
|
item
is the current item in the iteration.index
is the current index in the iteration.enumerable
is the enumerable object itself.
It should return true
to include the item in the results, false
otherwise.
Note that in addition to a callback, you can also pass an optional target
object that will be set as this
on the context. This is a good way
to give your iterator function access to the current object.
Parameters:
- callback Function
- The callback to execute
- target [Object]
- The target object to use
Returns:
- Array
- A filtered array.
filterBy
(key, value)
Array
public
Returns an array with just the items with the matched property. You
can pass an optional second argument with the target value. Otherwise
this will match any property that evaluates to true
.
Parameters:
- key String
- the property to test
- value [*]
- optional value to test against.
Returns:
- Array
- filtered array
find
(callback, target)
Object
public
Returns the first item in the array for which the callback returns true.
This method works similar to the filter()
method defined in JavaScript 1.6
except that it will stop working on the array once a match is found.
The callback method you provide should have the following signature (all parameters are optional):
1 |
function(item, index, enumerable);
|
item
is the current item in the iteration.index
is the current index in the iteration.enumerable
is the enumerable object itself.
It should return the true
to include the item in the results, false
otherwise.
Note that in addition to a callback, you can also pass an optional target
object that will be set as this
on the context. This is a good way
to give your iterator function access to the current object.
Parameters:
- callback Function
- The callback to execute
- target [Object]
- The target object to use
Returns:
- Object
- Found item or `undefined`.
findBy
(key, value)
Object
public
Returns the first item with a property matching the passed value. You
can pass an optional second argument with the target value. Otherwise
this will match any property that evaluates to true
.
This method works much like the more generic find()
method.
Returns:
- Object
- found item or `undefined`
forEach
(callback, target)
Object
public
Iterates through the enumerable, calling the passed function on each
item. This method corresponds to the forEach()
method defined in
JavaScript 1.6.
The callback method you provide should have the following signature (all parameters are optional):
1 |
function(item, index, enumerable);
|
item
is the current item in the iteration.index
is the current index in the iteration.enumerable
is the enumerable object itself.
Note that in addition to a callback, you can also pass an optional target
object that will be set as this
on the context. This is a good way
to give your iterator function access to the current object.
Parameters:
- callback Function
- The callback to execute
- target [Object]
- The target object to use
Returns:
- Object
- receiver
get
(keyName)
Object
public
Retrieves the value of a property from the object.
This method is usually similar to using object[keyName]
or object.keyName
,
however it supports both computed properties and the unknownProperty
handler.
Because get
unifies the syntax for accessing all these kinds
of properties, it can make many refactorings easier, such as replacing a
simple property with a computed property, or vice versa.
Computed Properties
Computed properties are methods defined with the property
modifier
declared at the end, such as:
1 2 3 |
fullName: function() { return this.get('firstName') + ' ' + this.get('lastName'); }.property('firstName', 'lastName') |
When you call get
on a computed property, the function will be
called and the return value will be returned instead of the function
itself.
Unknown Properties
Likewise, if you try to call get
on a property whose value is
undefined
, the unknownProperty()
method will be called on the object.
If this method returns any value other than undefined
, it will be returned
instead. This allows you to implement "virtual" properties that are
not defined upfront.
Parameters:
- keyName String
- The property to retrieve
Returns:
- Object
- The property value or undefined.
getEach
(key)
Array
public
Alias for mapBy
Parameters:
- key String
- name of the property
Returns:
- Array
- The mapped array.
getProperties
(list)
Object
public
To get the values of multiple properties at once, call getProperties
with a list of strings or an array:
1 2 |
record.getProperties('firstName', 'lastName', 'zipCode'); // { firstName: 'John', lastName: 'Doe', zipCode: '10011' } |
is equivalent to:
1 2 |
record.getProperties(['firstName', 'lastName', 'zipCode']); // { firstName: 'John', lastName: 'Doe', zipCode: '10011' } |
Parameters:
- list String...|Array
- of keys to get
Returns:
- Object
getWithDefault
(keyName, defaultValue)
Object
public
Retrieves the value of a property, or a default value in the case that the
property returns undefined
.
1 |
person.getWithDefault('lastName', 'Doe'); |
Parameters:
- keyName String
- The name of the property to retrieve
- defaultValue Object
- The value to return if the property value is undefined
Returns:
- Object
- The property value or the defaultValue.
hasObserverFor
(key)
Boolean
private
Returns true
if the object currently has observers registered for a
particular key. You can use this method to potentially defer performing
an expensive action until someone begins observing a particular property
on the object.
Parameters:
- key String
- Key to check
Returns:
- Boolean
incrementProperty
(keyName, increment)
Number
public
Set the value of a property to the current value plus some amount.
1 2 |
person.incrementProperty('age'); team.incrementProperty('score', 2); |
Parameters:
- keyName String
- The name of the property to increment
- increment Number
- The amount to increment by. Defaults to 1
Returns:
- Number
- The new property value
indexOf
(object, startAt)
Number
public
Returns the index of the given object's first occurrence.
If no startAt
argument is given, the starting location to
search is 0. If it's negative, will count backward from
the end of the array. Returns -1 if no match is found.
1 2 3 4 5 6 7 8 |
var arr = ['a', 'b', 'c', 'd', 'a']; arr.indexOf('a'); // 0 arr.indexOf('z'); // -1 arr.indexOf('a', 2); // 4 arr.indexOf('a', -1); // 4 arr.indexOf('b', 3); // -1 arr.indexOf('a', 100); // -1 |
Parameters:
- object Object
- the item to search for
- startAt Number
- optional starting location to search, default 0
Returns:
- Number
- index or -1 if not found
init
public
An overridable method called when objects are instantiated. By default, does nothing unless it is overridden during class definition.
Example:
1 2 3 4 5 6 7 8 9 10 11 |
App.Person = Ember.Object.extend({ init: function() { alert('Name is ' + this.get('name')); } }); var steve = App.Person.create({ name: "Steve" }); // alerts 'Name is Steve'. |
NOTE: If you do override init
for a framework class like Ember.View
,
be sure to call this._super(...arguments)
in your
init
declaration! If you don't, Ember may not have an opportunity to
do important setup work, and you'll see strange behavior in your
application.
insertAt
(idx, object)
Ember.Array
public
This will use the primitive replace()
method to insert an object at the
specified index.
1 2 3 4 |
var colors = ['red', 'green', 'blue']; colors.insertAt(2, 'yellow'); // ['red', 'green', 'yellow', 'blue'] colors.insertAt(5, 'orange'); // Error: Index out of range |
Parameters:
- idx Number
- index of insert the object at.
- object Object
- object to insert
Returns:
- Ember.Array
- receiver
invoke
(methodName, args)
Array
public
Invokes the named method on every object in the receiver that implements it. This method corresponds to the implementation in Prototype 1.6.
Parameters:
- methodName String
- the name of the method
- args Object...
- optional arguments to pass as well.
Returns:
- Array
- return values from calling invoke.
isAny
(key, value)
Boolean
public
Returns true
if the passed property resolves to the value of the second
argument for any item in the enumerable. This method is often simpler/faster
than using a callback.
Parameters:
Returns:
- Boolean
isEvery
(key, value)
Boolean
public
Returns true
if the passed property resolves to the value of the second
argument for all items in the enumerable. This method is often simpler/faster
than using a callback.
Parameters:
Returns:
- Boolean
lastIndexOf
(object, startAt)
Number
public
Returns the index of the given object's last occurrence.
If no startAt
argument is given, the search starts from
the last position. If it's negative, will count backward
from the end of the array. Returns -1 if no match is found.
1 2 3 4 5 6 7 8 |
var arr = ['a', 'b', 'c', 'd', 'a']; arr.lastIndexOf('a'); // 4 arr.lastIndexOf('z'); // -1 arr.lastIndexOf('a', 2); // 0 arr.lastIndexOf('a', -1); // 4 arr.lastIndexOf('b', 3); // 1 arr.lastIndexOf('a', 100); // 4 |
Parameters:
- object Object
- the item to search for
- startAt Number
- optional starting location to search, default 0
Returns:
- Number
- index or -1 if not found
map
(callback, target)
Array
public
Maps all of the items in the enumeration to another value, returning
a new array. This method corresponds to map()
defined in JavaScript 1.6.
The callback method you provide should have the following signature (all parameters are optional):
1 |
function(item, index, enumerable);
|
item
is the current item in the iteration.index
is the current index in the iteration.enumerable
is the enumerable object itself.
It should return the mapped value.
Note that in addition to a callback, you can also pass an optional target
object that will be set as this
on the context. This is a good way
to give your iterator function access to the current object.
Parameters:
- callback Function
- The callback to execute
- target [Object]
- The target object to use
Returns:
- Array
- The mapped array.
mapBy
(key)
Array
public
Similar to map, this specialized function returns the value of the named property on all items in the enumeration.
Parameters:
- key String
- name of the property
Returns:
- Array
- The mapped array.
metaForProperty
(key)
private
static
In some cases, you may want to annotate computed properties with additional metadata about how they function or what values they operate on. For example, computed property functions may close over variables that are then no longer available for introspection.
You can pass a hash of these values to a computed property like this:
1 2 3 4 |
person: function() { var personId = this.get('personId'); return App.Person.create({ id: personId }); }.property().meta({ type: App.Person }) |
Once you've done this, you can retrieve the values saved to the computed property from your class like this:
1 |
MyClass.metaForProperty('person');
|
This will return the original hash that was passed to meta()
.
Parameters:
- key String
- property name
nextObject
(index, previousObject, context)
Object
private
Required. You must implement this method to apply this mixin.
Implement this method to make your class enumerable.
This method will be called repeatedly during enumeration. The index value will always begin with 0 and increment monotonically. You don't have to rely on the index value to determine what object to return, but you should always check the value and start from the beginning when you see the requested index is 0.
The previousObject
is the object that was returned from the last call
to nextObject
for the current iteration. This is a useful way to
manage iteration if you are tracing a linked list, for example.
Finally the context parameter will always contain a hash you can use as a "scratchpad" to maintain any other state you need in order to iterate properly. The context object is reused and is not reset between iterations so make sure you setup the context with a fresh state whenever the index parameter is 0.
Generally iterators will continue to call nextObject
until the index
reaches the current length-1. If you run out of data before this
time for some reason, you should simply return undefined.
The default implementation of this method simply looks up the index. This works great on any Array-like objects.
Parameters:
- index Number
- the current index of the iteration
- previousObject Object
- the value returned by the last call to `nextObject`.
- context Object
- a context object you can use to maintain state.
Returns:
- Object
- the next object in the iteration or undefined
notifyPropertyChange
(keyName)
Ember.Observable
public
Convenience method to call propertyWillChange
and propertyDidChange
in
succession.
Parameters:
- keyName String
- The property key to be notified about.
Returns:
objectAt
(idx)
*
public
Returns the object at the given index
. If the given index
is negative
or is greater or equal than the array length, returns undefined
.
This is one of the primitives you must implement to support Ember.Array
.
If your object supports retrieving the value of an array item using get()
(i.e. myArray.get(0)
), then you do not need to implement this method
yourself.
1 2 3 4 5 6 7 |
var arr = ['a', 'b', 'c', 'd']; arr.objectAt(0); // 'a' arr.objectAt(3); // 'd' arr.objectAt(-1); // undefined arr.objectAt(4); // undefined arr.objectAt(5); // undefined |
Parameters:
- idx Number
- The index of the item to return.
Returns:
- *
- item at index or undefined
objectAtContent
(idx)
Object
private
Should actually retrieve the object at the specified index from the content. You can override this method in subclasses to transform the content item to something new.
This method will only be called if content is non-null
.
Parameters:
- idx Number
- The index to retrieve.
Returns:
- Object
- the value or undefined if none found
objectsAt
(indexes)
Array
public
This returns the objects at the specified indexes, using objectAt
.
1 2 3 4 |
var arr =Ā ['a', 'b', 'c', 'd']; arr.objectsAt([0, 1, 2]); // ['a', 'b', 'c'] arr.objectsAt([2, 3, 4]); // ['c', 'd', undefined] |
Parameters:
- indexes Array
- An array of indexes of items to return.
Returns:
- Array
popObject
public
Pop object from array or nil if none are left. Works just like pop()
but
it is KVO-compliant.
1 2 3 4 |
var colors = ['red', 'green', 'blue']; colors.popObject(); // 'blue' console.log(colors); // ['red', 'green'] |
Returns:
- object
propertyDidChange
(keyName)
Ember.Observable
private
Notify the observer system that a property has just changed.
Sometimes you need to change a value directly or indirectly without
actually calling get()
or set()
on it. In this case, you can use this
method and propertyWillChange()
instead. Calling these two methods
together will notify all observers that the property has potentially
changed value.
Note that you must always call propertyWillChange
and propertyDidChange
as a pair. If you do not, it may get the property change groups out of
order and cause notifications to be delivered more often than you would
like.
Parameters:
- keyName String
- The property key that has just changed.
Returns:
propertyWillChange
(keyName)
Ember.Observable
private
Notify the observer system that a property is about to change.
Sometimes you need to change a value directly or indirectly without
actually calling get()
or set()
on it. In this case, you can use this
method and propertyDidChange()
instead. Calling these two methods
together will notify all observers that the property has potentially
changed value.
Note that you must always call propertyWillChange
and propertyDidChange
as a pair. If you do not, it may get the property change groups out of
order and cause notifications to be delivered more often than you would
like.
Parameters:
- keyName String
- The property key that is about to change.
Returns:
pushObject
(obj)
public
Push the object onto the end of the array. Works just like push()
but it
is KVO-compliant.
1 2 3 4 |
var colors = ['red', 'green']; colors.pushObject('black'); // ['red', 'green', 'black'] colors.pushObject(['yellow']); // ['red', 'green', ['yellow']] |
Parameters:
- obj *
- object to push
Returns:
- object same object passed as a param
pushObjects
(objects)
Ember.Array
public
Add the objects in the passed numerable to the end of the array. Defers notifying observers of the change until all objects are added.
1 2 3 |
var colors = ['red']; colors.pushObjects(['yellow', 'orange']); // ['red', 'yellow', 'orange'] |
Parameters:
- objects Ember.Enumerable
- the objects to add
Returns:
- Ember.Array
- receiver
reduce
(callback, initialValue, reducerProperty)
Object
public
This will combine the values of the enumerator into a single value. It
is a useful way to collect a summary value from an enumeration. This
corresponds to the reduce()
method defined in JavaScript 1.8.
The callback method you provide should have the following signature (all parameters are optional):
1 |
function(previousValue, item, index, enumerable);
|
previousValue
is the value returned by the last call to the iterator.item
is the current item in the iteration.index
is the current index in the iteration.enumerable
is the enumerable object itself.
Return the new cumulative value.
In addition to the callback you can also pass an initialValue
. An error
will be raised if you do not pass an initial value and the enumerator is
empty.
Note that unlike the other methods, this method does not allow you to pass a target object to set as this for the callback. It's part of the spec. Sorry.
Parameters:
Returns:
- Object
- The reduced value.
reject
(callback, target)
Array
public
Returns an array with all of the items in the enumeration where the passed function returns false. This method is the inverse of filter().
The callback method you provide should have the following signature (all parameters are optional):
1 |
function(item, index, enumerable);
|
- item is the current item in the iteration.
- index is the current index in the iteration
- enumerable is the enumerable object itself.
It should return a falsey value to include the item in the results.
Note that in addition to a callback, you can also pass an optional target object that will be set as "this" on the context. This is a good way to give your iterator function access to the current object.
Parameters:
- callback Function
- The callback to execute
- target [Object]
- The target object to use
Returns:
- Array
- A rejected array.
rejectBy
(key, value)
Array
public
Returns an array with the items that do not have truthy values for key. You can pass an optional second argument with the target value. Otherwise this will match any property that evaluates to false.
Returns:
- Array
- rejected array
removeArrayObserver
(target, opts)
Ember.Array
public
Removes an array observer from the object if the observer is current registered. Calling this method multiple times with the same object will have no effect.
Parameters:
- target Object
- The object observing the array.
- opts Object
- Optional hash of configuration options including `willChange` and `didChange` option.
Returns:
- Ember.Array
- receiver
removeAt
(start, len)
Ember.Array
public
Remove an object at the specified index using the replace()
primitive
method. You can pass either a single index, or a start and a length.
If you pass a start and length that is beyond the
length this method will throw an OUT_OF_RANGE_EXCEPTION
.
1 2 3 4 5 |
var colors = ['red', 'green', 'blue', 'yellow', 'orange']; colors.removeAt(0); // ['green', 'blue', 'yellow', 'orange'] colors.removeAt(2, 2); // ['green', 'blue'] colors.removeAt(4, 2); // Error: Index out of range |
Parameters:
- start Number
- index, start of range
- len Number
- length of passing range
Returns:
- Ember.Array
- receiver
removeEnumerableObserver
(target, opts)
private
Removes a registered enumerable observer.
Parameters:
- target Object
- opts [Object]
Returns:
- this
removeObject
(obj)
Ember.Array
public
Remove all occurrences of an object in the array.
1 2 3 4 5 |
var cities = ['Chicago', 'Berlin', 'Lima', 'Chicago']; cities.removeObject('Chicago'); // ['Berlin', 'Lima'] cities.removeObject('Lima'); // ['Berlin'] cities.removeObject('Tokyo') // ['Berlin'] |
Parameters:
- obj *
- object to remove
Returns:
- Ember.Array
- receiver
removeObjects
(objects)
Object
public
Removes each object in the passed enumerable from the receiver.
Parameters:
- objects Ember.Enumerable
- the objects to remove
Returns:
- Object
- receiver
removeObserver
(key, target, method)
public
Remove an observer you have previously registered on this object. Pass
the same key, target, and method you passed to addObserver()
and your
target will no longer receive notifications.
Parameters:
- key String
- The key to observer
- target Object
- The target object to invoke
- method String|Function
- The method to invoke.
reopen
public
Augments a constructor's prototype with additional properties and functions:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 |
MyObject = Ember.Object.extend({ name: 'an object' }); o = MyObject.create(); o.get('name'); // 'an object' MyObject.reopen({ say: function(msg){ console.log(msg); } }) o2 = MyObject.create(); o2.say("hello"); // logs "hello" o.say("goodbye"); // logs "goodbye" |
To add functions and properties to the constructor itself,
see reopenClass
reopenClass
public
Augments a constructor's own properties and functions:
1 2 3 4 5 6 7 8 9 10 |
MyObject = Ember.Object.extend({ name: 'an object' }); MyObject.reopenClass({ canBuild: false }); MyObject.canBuild; // false o = MyObject.create(); |
In other words, this creates static properties and functions for the class. These are only available on the class and not on any instance of that class.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 |
App.Person = Ember.Object.extend({ name : "", sayHello : function() { alert("Hello. My name is " + this.get('name')); } }); App.Person.reopenClass({ species : "Homo sapiens", createPerson: function(newPersonsName){ return App.Person.create({ name:newPersonsName }); } }); var tom = App.Person.create({ name : "Tom Dale" }); var yehuda = App.Person.createPerson("Yehuda Katz"); tom.sayHello(); // "Hello. My name is Tom Dale" yehuda.sayHello(); // "Hello. My name is Yehuda Katz" alert(App.Person.species); // "Homo sapiens" |
Note that species
and createPerson
are not valid on the tom
and yehuda
variables. They are only valid on App.Person
.
To add functions and properties to instances of
a constructor by extending the constructor's prototype
see reopen
replace
(idx, amt, objects)
public
Required. You must implement this method to apply this mixin.
This is one of the primitives you must implement to support Ember.Array
.
You should replace amt objects started at idx with the objects in the
passed array. You should also call this.enumerableContentDidChange()
Parameters:
- idx Number
- Starting index in the array to replace. If idx >= length, then append to the end of the array.
- amt Number
- Number of elements that should be removed from the array, starting at *idx*.
- objects Array
- An array of zero or more objects that should be inserted into the array at *idx*
replaceContent
(idx, amt, objects)
Void
private
Should actually replace the specified objects on the content array. You can override this method in subclasses to transform the content item into something new.
This method will only be called if content is non-null
.
Parameters:
- idx Number
- The starting index
- amt Number
- The number of items to remove from the content.
- objects Array
- Optional array of objects to insert or null if no objects.
Returns:
- Void
reverseObjects
Ember.Array
public
Reverse objects in the array. Works just like reverse()
but it is
KVO-compliant.
Returns:
- Ember.Array
- receiver
set
(keyName, value)
Object
public
Sets the provided key or path to the value.
This method is generally very similar to calling object[key] = value
or
object.key = value
, except that it provides support for computed
properties, the setUnknownProperty()
method and property observers.
Computed Properties
If you try to set a value on a key that has a computed property handler
defined (see the get()
method for an example), then set()
will call
that method, passing both the value and key instead of simply changing
the value itself. This is useful for those times when you need to
implement a property that is composed of one or more member
properties.
Unknown Properties
If you try to set a value on a key that is undefined in the target
object, then the setUnknownProperty()
handler will be called instead. This
gives you an opportunity to implement complex "virtual" properties that
are not predefined on the object. If setUnknownProperty()
returns
undefined, then set()
will simply set the value on the object.
Property Observers
In addition to changing the property, set()
will also register a property
change with the object. Unless you have placed this call inside of a
beginPropertyChanges()
and endPropertyChanges(),
any "local" observers
(i.e. observer methods declared on the same object), will be called
immediately. Any "remote" observers (i.e. observer methods declared on
another object) will be placed in a queue and called at a later time in a
coalesced manner.
Parameters:
- keyName String
- The property to set
- value Object
- The value to set or `null`.
Returns:
- Object
- The passed value
setEach
(key, value)
Object
public
Sets the value on the named property for each member. This is more
efficient than using other methods defined on this helper. If the object
implements Ember.Observable, the value will be changed to set(),
otherwise
it will be set directly. null
objects are skipped.
Parameters:
- key String
- The key to set
- value Object
- The object to set
Returns:
- Object
- receiver
setObjects
(objects)
Ember.Array
public
Replace all the receiver's content with content of the argument. If argument is an empty array receiver will be cleared.
1 2 3 4 |
var colors = ['red', 'green', 'blue']; colors.setObjects(['black', 'white']); // ['black', 'white'] colors.setObjects([]); // [] |
Parameters:
- objects Ember.Array
- array whose content will be used for replacing the content of the receiver
Returns:
- Ember.Array
- receiver with the new content
setProperties
(hash)
Object
public
Sets a list of properties at once. These properties are set inside
a single beginPropertyChanges
and endPropertyChanges
batch, so
observers will be buffered.
1 |
record.setProperties({ firstName: 'Charles', lastName: 'Jolley' }); |
Parameters:
- hash Object
- the hash of keys and values to set
Returns:
- Object
- The passed in hash
shiftObject
public
Shift an object from start of array or nil if none are left. Works just
like shift()
but it is KVO-compliant.
1 2 3 4 |
var colors = ['red', 'green', 'blue']; colors.shiftObject(); // 'red' console.log(colors); // ['green', 'blue'] |
Returns:
- object
slice
(beginIndex, endIndex)
Array
public
Returns a new array that is a slice of the receiver. This implementation uses the observable array methods to retrieve the objects for the new slice.
1 2 3 4 5 |
var arr = ['red', 'green', 'blue']; arr.slice(0); // ['red', 'green', 'blue'] arr.slice(0, 2); // ['red', 'green'] arr.slice(1, 100); // ['green', 'blue'] |
Parameters:
- beginIndex Number
- (Optional) index to begin slicing from.
- endIndex Number
- (Optional) index to end the slice at (but not included).
Returns:
- Array
- New array with specified slice
sortBy
(property)
Array
public
Converts the enumerable into an array and sorts by the keys specified in the argument.
You may provide multiple arguments to sort by multiple properties.
Parameters:
- property String
- name(s) to sort on
Returns:
- Array
- The sorted array.
toArray
Array
public
Simply converts the enumerable into a genuine array. The order is not guaranteed. Corresponds to the method implemented by Prototype.
Returns:
- Array
- the enumerable as an array.
toString
String
public
Returns a string representation which attempts to provide more information
than Javascript's toString
typically does, in a generic way for all Ember
objects.
1 2 3 |
App.Person = Em.Object.extend()
person = App.Person.create()
person.toString() //=> "<App.Person:ember1024>"
|
If the object's class is not defined on an Ember namespace, it will indicate it is a subclass of the registered superclass:
1 2 3 |
Student = App.Person.extend()
student = Student.create()
student.toString() //=> "<(subclass of App.Person):ember1025>"
|
If the method toStringExtension
is defined, its return value will be
included in the output.
1 2 3 4 5 6 7 |
App.Teacher = App.Person.extend({ toStringExtension: function() { return this.get('fullName'); } }); teacher = App.Teacher.create() teacher.toString(); //=> "<App.Teacher:ember1026:Tom Dale>" |
Returns:
- String
- string representation
toggleProperty
(keyName)
Boolean
public
Set the value of a boolean property to the opposite of its current value.
1 |
starship.toggleProperty('warpDriveEngaged');
|
Parameters:
- keyName String
- The name of the property to toggle
Returns:
- Boolean
- The new property value
uniq
Ember.Enumerable
public
Returns a new enumerable that contains only unique values. The default implementation returns an array regardless of the receiver type.
1 2 |
var arr = ['a', 'a', 'b', 'b']; arr.uniq(); // ['a', 'b'] |
This only works on primitive data types, e.g. Strings, Numbers, etc.
Returns:
unshiftObject
(obj)
public
Unshift an object to start of array. Works just like unshift()
but it is
KVO-compliant.
1 2 3 4 |
var colors = ['red']; colors.unshiftObject('yellow'); // ['yellow', 'red'] colors.unshiftObject(['black']); // [['black'], 'yellow', 'red'] |
Parameters:
- obj *
- object to unshift
Returns:
- object same object passed as a param
unshiftObjects
(objects)
Ember.Array
public
Adds the named objects to the beginning of the array. Defers notifying observers until all objects have been added.
1 2 3 4 |
var colors = ['red']; colors.unshiftObjects(['black', 'white']); // ['black', 'white', 'red'] colors.unshiftObjects('yellow'); // Type Error: 'undefined' is not a function |
Parameters:
- objects Ember.Enumerable
- the objects to add
Returns:
- Ember.Array
- receiver
willDestroy
public
Override to implement teardown.
without
(value)
Ember.Enumerable
public
Returns a new enumerable that excludes the passed value. The default implementation returns an array regardless of the receiver type unless the receiver does not contain the value.
1 2 |
var arr = ['a', 'b', 'a', 'c']; arr.without('a'); // ['b', 'c'] |
Parameters:
- value Object
Returns:
@each
public
Returns a special object that can be used to observe individual properties on the array. Just get an equivalent property on this object and it will return an enumerable that maps automatically to the named key on the member objects.
@each
should only be used in a non-terminal context. Example:
1 2 3 |
myMethod: computed('posts.@each.author', function(){ ... }); |
If you merely want to watch for the array being changed, like an object being
replaced, added or removed, use []
instead of @each
.
1 2 3 |
myMethod: computed('posts.[]', function(){ ... }); |
[]
public
This is the handler for the special array content property. If you get this property, it will return this. If you set this property to a new array, it will replace the current content.
This property overrides the default property defined in Ember.Enumerable
.
Returns:
- this
arrangedContent
private
The array that the proxy pretends to be. In the default ArrayProxy
implementation, this and content
are the same. Subclasses of ArrayProxy
can override this property to provide things like sorting and filtering.
concatenatedProperties
Array
public
Defines the properties that will be concatenated from the superclass (instead of overridden).
By default, when you extend an Ember class a property defined in
the subclass overrides a property with the same name that is defined
in the superclass. However, there are some cases where it is preferable
to build up a property's value by combining the superclass' property
value with the subclass' value. An example of this in use within Ember
is the classNames
property of Ember.View
.
Here is some sample code showing the difference between a concatenated property and a normal one:
1 2 3 4 5 6 7 8 9 10 11 12 13 |
App.BarView = Ember.View.extend({ someNonConcatenatedProperty: ['bar'], classNames: ['bar'] }); App.FooBarView = App.BarView.extend({ someNonConcatenatedProperty: ['foo'], classNames: ['foo'] }); var fooBarView = App.FooBarView.create(); fooBarView.get('someNonConcatenatedProperty'); // ['foo'] fooBarView.get('classNames'); // ['ember-view', 'bar', 'foo'] |
This behavior extends to object creation as well. Continuing the above example:
1 2 3 4 5 6 |
var view = App.FooBarView.create({ someNonConcatenatedProperty: ['baz'], classNames: ['baz'] }) view.get('someNonConcatenatedProperty'); // ['baz'] view.get('classNames'); // ['ember-view', 'bar', 'foo', 'baz'] |
Adding a single property that is not an array will just add it in the array:
1 2 3 4 |
var view = App.FooBarView.create({ classNames: 'baz' }) view.get('classNames'); // ['ember-view', 'bar', 'foo', 'baz'] |
Using the concatenatedProperties
property, we can tell Ember to mix the
content of the properties.
In Ember.View
the classNameBindings
and attributeBindings
properties
are also concatenated, in addition to classNames
.
This feature is available for you to use throughout the Ember object model, although typical app developers are likely to use it infrequently. Since it changes expectations about behavior of properties, you should properly document its usage in each individual concatenated property (to not mislead your users to think they can override the property in a subclass).
Default: null
content
Ember.Array
private
The content array. Must be an object that implements Ember.Array
and/or
Ember.MutableArray.
firstObject
Object
public
Helper method returns the first object from a collection. This is usually used by bindings and other parts of the framework to extract a single object if the enumerable contains only one item.
If you override this method, you should implement it so that it will
always return the same value each time it is called. If your enumerable
contains only one object, this method should always return that object.
If your enumerable is empty, this method should return undefined
.
1 2 3 4 5 |
var arr = ['a', 'b', 'c']; arr.get('firstObject'); // 'a' var arr = []; arr.get('firstObject'); // undefined |
Returns:
- Object
- the object or undefined
hasArrayObservers
Boolean
public
Becomes true whenever the array currently has observers watching changes on the array.
hasEnumerableObservers
Boolean
private
Becomes true whenever the array currently has observers watching changes on the array.
isDestroyed
public
Destroyed object property flag.
if this property is true
the observers and bindings were already
removed by the effect of calling the destroy()
method.
Default: false
isDestroying
public
Destruction scheduled flag. The destroy()
method has been called.
The object stays intact until the end of the run loop at which point
the isDestroyed
flag is set.
Default: false
lastObject
Object
public
Helper method returns the last object from a collection. If your enumerable
contains only one object, this method should always return that object.
If your enumerable is empty, this method should return undefined
.
1 2 3 4 5 |
var arr = ['a', 'b', 'c']; arr.get('lastObject'); // 'c' var arr = []; arr.get('lastObject'); // undefined |
Returns:
- Object
- the last object or undefined
length
Number
public
Required. You must implement this method to apply this mixin.
Your array must support the length
property. Your replace methods should
set this property whenever it changes.
mergedProperties
Array
public
Defines the properties that will be merged from the superclass (instead of overridden).
By default, when you extend an Ember class a property defined in
the subclass overrides a property with the same name that is defined
in the superclass. However, there are some cases where it is preferable
to build up a property's value by merging the superclass property value
with the subclass property's value. An example of this in use within Ember
is the queryParams
property of routes.
Here is some sample code showing the difference between a merged property and a normal one:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 |
App.BarRoute = Ember.Route.extend({ someNonMergedProperty: { nonMerged: 'superclass value of nonMerged' }, queryParams: { page: {replace: false}, limit: {replace: true} } }); App.FooBarRoute = App.BarRoute.extend({ someNonMergedProperty: { completelyNonMerged: 'subclass value of nonMerged' }, queryParams: { limit: {replace: false} } }); var fooBarRoute = App.FooBarRoute.create(); fooBarRoute.get('someNonMergedProperty'); // => { completelyNonMerged: 'subclass value of nonMerged' } // // Note the entire object, including the nonMerged property of // the superclass object, has been replaced fooBarRoute.get('queryParams'); // => { // page: {replace: false}, // limit: {replace: false} // } // // Note the page remains from the superclass, and the // `limit` property's value of `false` has been merged from // the subclass. |
This behavior is not available during object create
calls. It is only
available at extend
time.
This feature is available for you to use throughout the Ember object model, although typical app developers are likely to use it infrequently. Since it changes expectations about behavior of properties, you should properly document its usage in each individual merged property (to not mislead your users to think they can override the property in a subclass).
Default: null