Class Ember.Enumerable private

Defined in: packages/ember-runtime/lib/mixins/enumerable.js:60

Module: ember

Since: vEmber 0.9

This mixin defines the common interface implemented by enumerable objects in Ember. Most of these methods follow the standard Array iteration API defined up to JavaScript 1.8 (excluding language-specific features that cannot be emulated in older versions of JavaScript).

This mixin is applied automatically to the Array class on page load, so you can use any of these methods on simple arrays. If Array already implements one of these methods, the mixin will not override them.

Writing Your Own Enumerable

To make your own custom class enumerable, you need two items:

You must have a length property. This property should change whenever the number of items in your enumerable object changes. If you use this with an Ember.Object subclass, you should be sure to change the length property using set().
You must implement nextObject(). See documentation.

Once you have these two methods implemented, apply the Ember.Enumerable mixin to your class and you will be able to enumerate the contents of your object like any other collection.

Using Ember Enumeration with Other Libraries

Many other libraries provide some kind of iterator or enumeration like facility. This is often where the most common API conflicts occur. Ember's API is designed to be as friendly as possible with other libraries by implementing only methods that mostly correspond to the JavaScript 1.8 API.

Methods

compact : Array public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:914

returns: Array; the array without null and undefined elements.

Returns a copy of the array with all null and undefined elements removed.

var arr = ['a', null, 'c', undefined];
arr.compact();  // ['a', 'c']

contains (obj) : Boolean public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:213

obj: Object; The object to search for.
returns: Boolean; true if object is found in enumerable.

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.

var arr = ['a', 'b', 'c'];

arr.contains('a'); // true
arr.contains('z'); // false

every (callback, target) : Boolean public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:613

callback: Function; The callback to execute
target: Object; The target object to use
returns: Boolean

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):

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:

if (people.every(isEngineer)) {
  Paychecks.addBigBonus();
}

filter (callback, target) : Array public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:381

callback: Function; The callback to execute
target: Object; The target object to use
returns: Array; A filtered array.

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):

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.

filterBy (key, value) : Array public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:455

key: String; the property to test
value: *; optional value to test against.
returns: Array; filtered array

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.

find (callback, target) : Object public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:523

callback: Function; The callback to execute
target: Object; The target object to use
returns: Object; Found item or undefined.

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):

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.

findBy (key, value) : Object public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:580

key: String; the property to test
value: String; optional value to test against.
returns: Object; found item or undefined

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.

forEach (callback, target) : Object public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:238

callback: Function; The callback to execute
target: Object; The target object to use
returns: Object; receiver

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):

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.

getEach (key) : Array public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:289

key: String; name of the property
returns: Array; The mapped array.

Alias for mapBy

isEvery (key, value) : Boolean public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:674

Available since v1.3.0

key: String; the property to test
value: String; optional value to test against. Defaults to true
returns: Boolean

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.

map (callback, target) : Array public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:317

callback: Function; The callback to execute
target: Object; The target object to use
returns: Array; The mapped array.

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):

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.

mapBy (key) : Array public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:354

key: String; name of the property
returns: Array; The mapped array.

Similar to map, this specialized function returns the value of the named property on all items in the enumeration.

reject (callback, target) : Array public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:422

callback: Function; The callback to execute
target: Object; The target object to use
returns: Array; A rejected array.

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):

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.

rejectBy (key, value) : Array public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:484

key: String; the property to test
value: String; optional value to test against.
returns: Array; rejected array

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.

setEach (key, value) : Object public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:299

key: String; The key to set
value: Object; The object to set
returns: Object; receiver

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.

sortBy (property) : Array public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:1189

Available since v1.2.0

property: String; name(s) to sort on
returns: Array; The sorted array.

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.

without (value) : Ember.Enumerable public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:932

value: Object
returns: Ember.Enumerable

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.

var arr = ['a', 'b', 'a', 'c'];
arr.without('a');  // ['b', 'c']

Properties

firstObject : Object public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:138

returns: Object; the object or undefined

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.

var arr = ['a', 'b', 'c'];
arr.get('firstObject');  // 'a'

var arr = [];
arr.get('firstObject');  // undefined

lastObject : Object public

Module: ember

Defined in packages/ember-runtime/lib/mixins/enumerable.js:174

returns: Object; the last object or undefined

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.

var arr = ['a', 'b', 'c'];
arr.get('lastObject');  // 'c'

var arr = [];
arr.get('lastObject');  // undefined