Class ArrayProxy
publicimport ArrayProxy from '@ember/array/proxy';
An ArrayProxy wraps any other object that implements Array
and/or
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:
import { A } from '@ember/array';
import ArrayProxy from '@ember/array/proxy';
let pets = ['dog', 'cat', 'fish'];
let ap = ArrayProxy.create({ content: 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
:
import { A } from '@ember/array';
import ArrayProxy from '@ember/array/proxy';
let pets = ['dog', 'cat', 'fish'];
let ap = ArrayProxy.create({
content: A(pets),
objectAtContent: function(idx) {
return this.get('content').objectAt(idx).toUpperCase();
}
});
ap.get('firstObject'); // . 'DOG'
When overriding this class, it is important to place the call to
_super
after setting content
so the internal observers have
a chance to fire properly:
import { A } from '@ember/array';
import ArrayProxy from '@ember/array/proxy';
export default ArrayProxy.extend({
init() {
this.set('content', A(['dog', 'cat', 'fish']));
this._super(...arguments);
}
});
[] public
Inherited from EmberArray packages/@ember/array/index.ts:304
- returns
this
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.
let peopleToMoon = ['Armstrong', 'Aldrin'];
peopleToMoon.get('[]'); // ['Armstrong', 'Aldrin']
peopleToMoon.set('[]', ['Collins']); // ['Collins']
peopleToMoon.get('[]'); // ['Collins']
arrangedContent public
Defined in packages/@ember/array/proxy.ts:129
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 public
Inherited from CoreObject packages/@ember/object/core.ts:353
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 Component
from @ember/component
.
Here is some sample code showing the difference between a concatenated property and a normal one:
import EmberObject from '@ember/object';
const Bar = EmberObject.extend({
// Configure which properties to concatenate
concatenatedProperties: ['concatenatedProperty'],
someNonConcatenatedProperty: ['bar'],
concatenatedProperty: ['bar']
});
const FooBar = Bar.extend({
someNonConcatenatedProperty: ['foo'],
concatenatedProperty: ['foo']
});
let fooBar = FooBar.create();
fooBar.get('someNonConcatenatedProperty'); // ['foo']
fooBar.get('concatenatedProperty'); // ['bar', 'foo']
This behavior extends to object creation as well. Continuing the above example:
let fooBar = FooBar.create({
someNonConcatenatedProperty: ['baz'],
concatenatedProperty: ['baz']
})
fooBar.get('someNonConcatenatedProperty'); // ['baz']
fooBar.get('concatenatedProperty'); // ['bar', 'foo', 'baz']
Adding a single property that is not an array will just add it in the array:
let fooBar = FooBar.create({
concatenatedProperty: 'baz'
})
view.get('concatenatedProperty'); // ['bar', 'foo', 'baz']
Using the concatenatedProperties
property, we can tell Ember to mix the
content of the properties.
In Component
the classNames
, classNameBindings
and
attributeBindings
properties are concatenated.
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).
content public
Defined in packages/@ember/array/proxy.ts:120
The content array. Must be an object that implements Array
and/or
MutableArray.
firstObject Object | undefined public
Inherited from EmberArray packages/@ember/array/index.ts:324
- returns
- Object | undefined
The first object in the array
The first object in the array, or undefined
if the array is empty.
let vowels = ['a', 'e', 'i', 'o', 'u'];
vowels.firstObject; // 'a'
vowels.shiftObject();
vowels.firstObject; // 'e'
vowels.reverseObjects();
vowels.firstObject; // 'u'
vowels.clear();
vowels.firstObject; // undefined
isDestroyed public
Inherited from CoreObject packages/@ember/object/core.ts:502
Destroyed object property flag.
if this property is true
the observers and bindings were already
removed by the effect of calling the destroy()
method.
isDestroying public
Inherited from CoreObject packages/@ember/object/core.ts:520
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.
lastObject Object | undefined public
Inherited from EmberArray packages/@ember/array/index.ts:346
- returns
- Object | undefined
The last object in the array
The last object in the array, or undefined
if the array is empty.
length public
Inherited from EmberArray packages/@ember/array/index.ts:253
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 public
Inherited from CoreObject packages/@ember/object/core.ts:427
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:
import EmberObject from '@ember/object';
const Bar = EmberObject.extend({
// Configure which properties are to be merged
mergedProperties: ['mergedProperty'],
someNonMergedProperty: {
nonMerged: 'superclass value of nonMerged'
},
mergedProperty: {
page: { replace: false },
limit: { replace: true }
}
});
const FooBar = Bar.extend({
someNonMergedProperty: {
completelyNonMerged: 'subclass value of nonMerged'
},
mergedProperty: {
limit: { replace: false }
}
});
let fooBar = FooBar.create();
fooBar.get('someNonMergedProperty');
// => { completelyNonMerged: 'subclass value of nonMerged' }
//
// Note the entire object, including the nonMerged property of
// the superclass object, has been replaced
fooBar.get('mergedProperty');
// => {
// 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.
In Route
the queryParams
property is merged.
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).