@ember/object/computed - 4.12 - Ember API Documentation

alias (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:649

import { alias } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computed property which creates an alias to the original value for property.

Creates a new property that is an alias for another property on an object. Calls to get or set this property behave as though they were called on the original property.

Example:

        
              import { set } from '@ember/object';
import { alias } from '@ember/object/computed';

class Person {
  name = 'Alex Matchneer';

  @alias('name') nomen;
}

let alex = new Person();

alex.nomen; // 'Alex Matchneer'
alex.name;  // 'Alex Matchneer'

set(alex, 'nomen', '@machty');
alex.name;  // '@machty'

and (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:560

import { and } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computed property which performs a logical `and` on the values of all the original values for properties.

A computed property that performs a logical and on the original values for the provided dependent properties.

You may pass in more than two properties and even use property brace expansion. The computed property will return the first falsy value or last truthy value just like JavaScript's && operator.

Example:

        
              import { set } from '@ember/object';
import { and } from '@ember/object/computed';

class Hamster {
  @and('hasTent', 'hasBackpack') readyForCamp;
  @and('hasWalkingStick', 'hasBackpack') readyForHike;
}

let tomster = new Hamster();

tomster.readyForCamp; // false

set(tomster, 'hasTent', true);
tomster.readyForCamp; // false

set(tomster, 'hasBackpack', true);
tomster.readyForCamp; // true

set(tomster, 'hasBackpack', 'Yes');
tomster.readyForCamp; // 'Yes'

set(tomster, 'hasWalkingStick', null);
tomster.readyForHike; // null

bool (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:240

import { bool } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computed property which converts to boolean the original value for property

A computed property that converts the provided dependent property into a boolean value.

Example:

        
              import { set } from '@ember/object';
import { bool } from '@ember/object/computed';

class Hamster {
  @bool('numBananas') hasBananas
}

let hamster = new Hamster();

hamster.hasBananas; // false

set(hamster, 'numBananas', 0);
hamster.hasBananas; // false

set(hamster, 'numBananas', 1);
hamster.hasBananas; // true

set(hamster, 'numBananas', null);
hamster.hasBananas; // false

collect (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:980

import { collect } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computed property which maps values of all passed in properties to an array.

A computed property that returns the array of values for the provided dependent properties.

Example:

        
              import { set } from '@ember/object';
import { collect } from '@ember/object/computed';

class Hamster {
  @collect('hat', 'shirt') clothes;
}

let hamster = new Hamster();

hamster.clothes; // [null, null]

set(hamster, 'hat', 'Camp Hat');
set(hamster, 'shirt', 'Camp Shirt');
hamster.clothes; // ['Camp Hat', 'Camp Shirt']

deprecatingAlias (dependentKey, options) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:796

Available since v1.7.0

import { deprecatingAlias } from '@ember/object/computed';

dependentKey: String
options: Object; Options for `deprecate`.
returns: ComputedProperty; computed property which creates an alias with a deprecation to the original value for property.

Creates a new property that is an alias for another property on an object. Calls to get or set this property behave as though they were called on the original property, but also print a deprecation warning.

Example:

        
              import { set } from '@ember/object';
import { deprecatingAlias } from '@ember/object/computed';

class Hamster {
  @deprecatingAlias('cavendishCount', {
    id: 'hamster.deprecate-banana',
    until: '3.0.0'
  })
  bananaCount;
}

let hamster = new Hamster();

set(hamster, 'bananaCount', 5); // Prints a deprecation warning.
hamster.cavendishCount; // 5

empty (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:60

Available since v1.6.0

import { empty } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computed property which returns true if the value of the dependent property is null, an empty string, empty array, or empty function and false if the underlying value is not empty.

A computed property macro that returns true if the value of the dependent property is null, an empty string, empty array, or empty function.

Example:

        
              import { set } from '@ember/object';
import { empty } from '@ember/object/computed';

class ToDoList {
  constructor(todos) {
    set(this, 'todos', todos);
  }

  @empty('todos') isDone;
}

let todoList = new ToDoList(
  ['Unit Test', 'Documentation', 'Release']
);

todoList.isDone; // false
set(todoList, 'todos', []);
todoList.isDone; // true

equal (dependentKey, value) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:335

import { equal } from '@ember/object/computed';

dependentKey: String
value: String|Number|Object
returns: ComputedProperty; computed property which returns true if the original value for property is equal to the given value.

A computed property that returns true if the provided dependent property is equal to the given value.

Example:

        
              import { set } from '@ember/object';
import { equal } from '@ember/object/computed';

class Hamster {
  @equal('percentCarrotsEaten', 100) satisfied;
}

let hamster = new Hamster();

hamster.satisfied; // false

set(hamster, 'percentCarrotsEaten', 100);
hamster.satisfied; // true

set(hamster, 'percentCarrotsEaten', 50);
hamster.satisfied; // false

expandProperties (pattern, callback) public

Module: @ember/object

Defined in packages/@ember/-internals/metal/lib/expand_properties.ts:9

import { expandProperties } from '@ember/object/computed';

pattern: String; The property pattern to expand.
callback: Function; The callback to invoke. It is invoked once per expansion, and is passed the expansion.

Expands pattern, invoking callback for each expansion.

The only pattern supported is brace-expansion, anything else will be passed once to callback directly.

Example

        
              import { expandProperties } from '@ember/object/computed';

function echo(arg){ console.log(arg); }

expandProperties('foo.bar', echo);              //=> 'foo.bar'
expandProperties('{foo,bar}', echo);            //=> 'foo', 'bar'
expandProperties('foo.{bar,baz}', echo);        //=> 'foo.bar', 'foo.baz'
expandProperties('{foo,bar}.baz', echo);        //=> 'foo.baz', 'bar.baz'
expandProperties('foo.{bar,baz}.[]', echo)      //=> 'foo.bar.[]', 'foo.baz.[]'
expandProperties('{foo,bar}.{spam,eggs}', echo) //=> 'foo.spam', 'foo.eggs', 'bar.spam', 'bar.eggs'
expandProperties('{foo}.bar.{baz}')             //=> 'foo.bar.baz'

filter (dependentKey, additionalDependentKeys, callback) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:431

import { filter } from '@ember/object/computed';

dependentKey: String
additionalDependentKeys: Array; optional array of additional dependent keys
callback: Function
returns: ComputedProperty; the filtered array

Filters the array by the callback, like the Array.prototype.filter method.

The callback method you provide should have the following signature:

item is the current item in the iteration.
index is the integer index of the current item in the iteration.
array is the dependant array itself.

        
              function filterCallback(item, index, array);

In the callback, return a truthy value that coerces to true to keep the element, or a falsy to reject it.

Example:

        
          
              
              import { set } from '@ember/object';
import { filter } from '@ember/object/computed';

class Hamster {
  constructor(chores) {
    set(this, 'chores', chores);
  }

  @filter('chores', function(chore, index, array) {
    return !chore.done;
  })
  remainingChores;
}

let hamster = Hamster.create([
  { name: 'cook', done: true },
  { name: 'clean', done: true },
  { name: 'write more unit tests', done: false }
]);

hamster.remainingChores; // [{name: 'write more unit tests', done: false}]
            

        
      

You can also use @each.property in your dependent key, the callback will still use the underlying array:

        
          
              
              import { set } from '@ember/object';
import { filter } from '@ember/object/computed';

class Hamster {
  constructor(chores) {
    set(this, 'chores', chores);
  }

  @filter('chores.@each.done', function(chore, index, array) {
    return !chore.done;
  })
  remainingChores;
}

let hamster = new Hamster([
  { name: 'cook', done: true },
  { name: 'clean', done: true },
  { name: 'write more unit tests', done: false }
]);
hamster.remainingChores; // [{name: 'write more unit tests', done: false}]

set(hamster.chores[2], 'done', true);
hamster.remainingChores; // []
            

        
      

Finally, you can optionally pass an array of additional dependent keys as the second parameter to the macro, if your filter function relies on any external values:

        
              import { filter } from '@ember/object/computed';

class Hamster {
  constructor(chores) {
    set(this, 'chores', chores);
  }

  doneKey = 'finished';

  @filter('chores', ['doneKey'], function(chore, index, array) {
    return !chore[this.doneKey];
  })
  remainingChores;
}

let hamster = new Hamster([
  { name: 'cook', finished: true },
  { name: 'clean', finished: true },
  { name: 'write more unit tests', finished: false }
]);

hamster.remainingChores; // [{name: 'write more unit tests', finished: false}]

filterBy (dependentKey, propertyKey, value) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:601

import { filterBy } from '@ember/object/computed';

dependentKey: String
propertyKey: String
value: *
returns: ComputedProperty; the filtered array

Filters the array by the property and value.

Example:

        
              import { set } from '@ember/object';
import { filterBy } from '@ember/object/computed';

class Hamster {
  constructor(chores) {
    set(this, 'chores', chores);
  }

  @filterBy('chores', 'done', false) remainingChores;
}

let hamster = new Hamster([
  { name: 'cook', done: true },
  { name: 'clean', done: true },
  { name: 'write more unit tests', done: false }
]);

hamster.remainingChores; // [{ name: 'write more unit tests', done: false }]

gt (dependentKey, value) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:380

import { gt } from '@ember/object/computed';

dependentKey: String
value: Number
returns: ComputedProperty; computed property which returns true if the original value for property is greater than given value.

A computed property that returns true if the provided dependent property is greater than the provided value.

Example:

        
              import { set } from '@ember/object';
import { gt } from '@ember/object/computed';

class Hamster {
  @gt('numBananas', 10) hasTooManyBananas;
}

let hamster = new Hamster();

hamster.hasTooManyBananas; // false

set(hamster, 'numBananas', 3);
hamster.hasTooManyBananas; // false

set(hamster, 'numBananas', 11);
hamster.hasTooManyBananas; // true

gte (dependentKey, value) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:425

import { gte } from '@ember/object/computed';

dependentKey: String
value: Number
returns: ComputedProperty; computed property which returns true if the original value for property is greater or equal then given value.

A computed property that returns true if the provided dependent property is greater than or equal to the provided value.

Example:

        
              import { set } from '@ember/object';
import { gte } from '@ember/object/computed';

class Hamster {
  @gte('numBananas', 10) hasTooManyBananas;
}

let hamster = new Hamster();

hamster.hasTooManyBananas; // false

set(hamster, 'numBananas', 3);
hamster.hasTooManyBananas; // false

set(hamster, 'numBananas', 10);
hamster.hasTooManyBananas; // true

intersect (propertyKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:829

import { intersect } from '@ember/object/computed';

propertyKey: String
returns: ComputedProperty; computes a new array with all the duplicated elements from the dependent arrays

A computed property which returns a new array with all the elements two or more dependent arrays have in common.

Example:

        
              import { set } from '@ember/object';
import { intersect } from '@ember/object/computed';

class FriendGroups {
  constructor(adaFriends, charlesFriends) {
    set(this, 'adaFriends', adaFriends);
    set(this, 'charlesFriends', charlesFriends);
  }

  @intersect('adaFriends', 'charlesFriends') friendsInCommon;
}

let groups = new FriendGroups(
  ['Charles Babbage', 'John Hobhouse', 'William King', 'Mary Somerville'],
  ['William King', 'Mary Somerville', 'Ada Lovelace', 'George Peacock']
);

groups.friendsInCommon; // ['William King', 'Mary Somerville']

lt (dependentKey, value) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:470

import { lt } from '@ember/object/computed';

dependentKey: String
value: Number
returns: ComputedProperty; computed property which returns true if the original value for property is less then given value.

A computed property that returns true if the provided dependent property is less than the provided value.

Example:

        
              import { set } from '@ember/object';
import { lt } from '@ember/object/computed';

class Hamster {
  @lt('numBananas', 3) needsMoreBananas;
}

let hamster = new Hamster();

hamster.needsMoreBananas; // true

set(hamster, 'numBananas', 3);
hamster.needsMoreBananas; // false

set(hamster, 'numBananas', 2);
hamster.needsMoreBananas; // true

lte (dependentKey, value) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:515

import { lte } from '@ember/object/computed';

dependentKey: String
value: Number
returns: ComputedProperty; computed property which returns true if the original value for property is less or equal than given value.

A computed property that returns true if the provided dependent property is less than or equal to the provided value.

Example:

        
              import { set } from '@ember/object';
import { lte } from '@ember/object/computed';

class Hamster {
  @lte('numBananas', 3) needsMoreBananas;
}

let hamster = new Hamster();

hamster.needsMoreBananas; // true

set(hamster, 'numBananas', 5);
hamster.needsMoreBananas; // false

set(hamster, 'numBananas', 3);
hamster.needsMoreBananas; // true

map (dependentKey, additionalDependentKeys, callback) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:240

import { map } from '@ember/object/computed';

dependentKey: String
additionalDependentKeys: Array; optional array of additional dependent keys
callback: Function
returns: ComputedProperty; an array mapped via the callback

Returns an array mapped via the callback

The callback method you provide should have the following signature:

item is the current item in the iteration.
index is the integer index of the current item in the iteration.

        
              function mapCallback(item, index);

Example:

        
              import { set } from '@ember/object';
import { map } from '@ember/object/computed';

class Hamster {
  constructor(chores) {
    set(this, 'chores', chores);
  }

  @map('chores', function(chore, index) {
    return `${chore.toUpperCase()}!`;
  })
  excitingChores;
});

let hamster = new Hamster(['clean', 'write more unit tests']);

hamster.excitingChores; // ['CLEAN!', 'WRITE MORE UNIT TESTS!']

You can optionally pass an array of additional dependent keys as the second parameter to the macro, if your map function relies on any external values:

        
          
              
              import { set } from '@ember/object';
import { map } from '@ember/object/computed';

class Hamster {
  shouldUpperCase = false;

  constructor(chores) {
    set(this, 'chores', chores);
  }

  @map('chores', ['shouldUpperCase'], function(chore, index) {
    if (this.shouldUpperCase) {
      return `${chore.toUpperCase()}!`;
    } else {
      return `${chore}!`;
    }
  })
  excitingChores;
}

let hamster = new Hamster(['clean', 'write more unit tests']);

hamster.excitingChores; // ['clean!', 'write more unit tests!']

set(hamster, 'shouldUpperCase', true);
hamster.excitingChores; // ['CLEAN!', 'WRITE MORE UNIT TESTS!']
            

        
      

mapBy (dependentKey, propertyKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:364

import { mapBy } from '@ember/object/computed';

dependentKey: String
propertyKey: String
returns: ComputedProperty; an array mapped to the specified key

Returns an array mapped to the specified key.

Example:

        
          
              
              import { set } from '@ember/object';
import { mapBy } from '@ember/object/computed';

class Person {
  children = [];

  @mapBy('children', 'age') childAges;
}

let lordByron = new Person();

lordByron.childAges; // []

set(lordByron, 'children', [
  {
    name: 'Augusta Ada Byron',
    age: 7
  }
]);
lordByron.childAges; // [7]

set(lordByron, 'children', [
  ...lordByron.children,
  {
    name: 'Allegra Byron',
    age: 5
  }, {
    name: 'Elizabeth Medora Leigh',
    age: 8
  }
]);
lordByron.childAges; // [7, 5, 8]
            

        
      

match (dependentKey, regexp) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:288

import { match } from '@ember/object/computed';

dependentKey: String
regexp: RegExp
returns: ComputedProperty; computed property which match the original value for property against a given RegExp

A computed property which matches the original value for the dependent property against a given RegExp, returning true if the value matches the RegExp and false if it does not.

Example:

        
              import { set } from '@ember/object';
import { match } from '@ember/object/computed';

class User {
  @match('email', /^.+@.+\..+$/) hasValidEmail;
}

let user = new User();

user.hasValidEmail; // false

set(user, 'email', '');
user.hasValidEmail; // false

set(user, 'email', 'ember_hamster@example.com');
user.hasValidEmail; // true

max (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:113

import { max } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computes the largest value in the dependentKey's array

A computed property that calculates the maximum value in the dependent array. This will return -Infinity when the dependent array is empty.

Example:

        
          
              
              import { set } from '@ember/object';
import { mapBy, max } from '@ember/object/computed';

class Person {
  children = [];

  @mapBy('children', 'age') childAges;
  @max('childAges') maxChildAge;
}

let lordByron = new Person();

lordByron.maxChildAge; // -Infinity

set(lordByron, 'children', [
  {
    name: 'Augusta Ada Byron',
    age: 7
  }
]);
lordByron.maxChildAge; // 7

set(lordByron, 'children', [
  ...lordByron.children,
  {
    name: 'Allegra Byron',
    age: 5
  }, {
    name: 'Elizabeth Medora Leigh',
    age: 8
  }
]);
lordByron.maxChildAge; // 8
            

        
      

If the types of the arguments are not numbers, they will be converted to numbers and the type of the return value will always be Number. For example, the max of a list of Date objects will be the highest timestamp as a Number. This behavior is consistent with Math.max.

min (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:177

import { min } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computes the smallest value in the dependentKey's array

A computed property that calculates the minimum value in the dependent array. This will return Infinity when the dependent array is empty.

Example:

        
          
              
              import { set } from '@ember/object';
import { mapBy, min } from '@ember/object/computed';

class Person {
  children = [];

  @mapBy('children', 'age') childAges;
  @min('childAges') minChildAge;
}

let lordByron = Person.create({ children: [] });

lordByron.minChildAge; // Infinity

set(lordByron, 'children', [
  {
    name: 'Augusta Ada Byron',
    age: 7
  }
]);
lordByron.minChildAge; // 7

set(lordByron, 'children', [
  ...lordByron.children,
  {
    name: 'Allegra Byron',
    age: 5
  }, {
    name: 'Elizabeth Medora Leigh',
    age: 8
  }
]);
lordByron.minChildAge; // 5
            

        
      

If the types of the arguments are not numbers, they will be converted to numbers and the type of the return value will always be Number. For example, the min of a list of Date objects will be the lowest timestamp as a Number. This behavior is consistent with Math.min.

none (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:155

import { none } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computed property which returns true if original value for property is null or undefined.

A computed property that returns true if the value of the dependent property is null or undefined. This avoids errors from JSLint complaining about use of ==, which can be technically confusing.

        
              import { set } from '@ember/object';
import { none } from '@ember/object/computed';

class Hamster {
  @none('food') isHungry;
}

let hamster = new Hamster();

hamster.isHungry; // true

set(hamster, 'food', 'Banana');
hamster.isHungry; // false

set(hamster, 'food', null);
hamster.isHungry; // true

not (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:198

import { not } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computed property which returns inverse of the original value for property

A computed property that returns the inverse boolean value of the original value for the dependent property.

Example:

        
              import { set } from '@ember/object';
import { not } from '@ember/object/computed';

class User {
  loggedIn = false;

  @not('loggedIn') isAnonymous;
}

let user = new User();

user.isAnonymous; // true
set(user, 'loggedIn', true);
user.isAnonymous; // false

notEmpty (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:109

import { notEmpty } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computed property which returns true if original value for property is not empty.

A computed property that returns true if the value of the dependent property is NOT null, an empty string, empty array, or empty function.

Example:

        
              import { set } from '@ember/object';
import { notEmpty } from '@ember/object/computed';

class Hamster {
  constructor(backpack) {
    set(this, 'backpack', backpack);
  }

  @notEmpty('backpack') hasStuff
}

let hamster = new Hamster(
  ['Food', 'Sleeping Bag', 'Tent']
);

hamster.hasStuff; // true
set(hamster, 'backpack', []);
hamster.hasStuff; // false

oneWay (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:684

import { oneWay } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computed property which creates a one way computed property to the original value for property.

Where the alias computed macro aliases get and set, and allows for bidirectional data flow, the oneWay computed macro only provides an aliased get. The set will not mutate the upstream property, rather causes the current property to become the value set. This causes the downstream property to permanently diverge from the upstream property.

Example:

        
              import { set } from '@ember/object';
import { oneWay }from '@ember/object/computed';

class User {
  constructor(firstName, lastName) {
    set(this, 'firstName', firstName);
    set(this, 'lastName', lastName);
  }

  @oneWay('firstName') nickName;
}

let teddy = new User('Teddy', 'Zeenny');

teddy.nickName; // 'Teddy'

set(teddy, 'nickName', 'TeddyBear');
teddy.firstName; // 'Teddy'
teddy.nickName; // 'TeddyBear'

or (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:606

import { or } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computed property which performs a logical `or` on the values of all the original values for properties.

A computed property which performs a logical or on the original values for the provided dependent properties.

You may pass in more than two properties and even use property brace expansion. The computed property will return the first truthy value or last falsy value just like JavaScript's || operator.

Example:

        
              import { set } from '@ember/object';
import { or } from '@ember/object/computed';

class Hamster {
  @or('hasJacket', 'hasUmbrella') readyForRain;
  @or('hasSunscreen', 'hasUmbrella') readyForBeach;
}

let tomster = new Hamster();

tomster.readyForRain; // undefined

set(tomster, 'hasUmbrella', true);
tomster.readyForRain; // true

set(tomster, 'hasJacket', 'Yes');
tomster.readyForRain; // 'Yes'

set(tomster, 'hasSunscreen', 'Check');
tomster.readyForBeach; // 'Check'

readOnly (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:745

Available since v1.5.0

import { readOnly } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computed property which creates a one way computed property to the original value for property.

Where oneWay computed macro provides oneWay bindings, the readOnly computed macro provides a readOnly one way binding. Very often when using the oneWay macro one does not also want changes to propagate back up, as they will replace the value.

This prevents the reverse flow, and also throws an exception when it occurs.

Example:

        
              import { set } from '@ember/object';
import { readOnly } from '@ember/object/computed';

class User {
  constructor(firstName, lastName) {
    set(this, 'firstName', firstName);
    set(this, 'lastName', lastName);
  }

  @readOnly('firstName') nickName;
});

let teddy = new User('Teddy', 'Zeenny');

teddy.nickName; // 'Teddy'

set(teddy, 'nickName', 'TeddyBear'); // throws Exception
// throw new EmberError('Cannot Set: nickName on: <User:ember27288>' );`

teddy.firstName; // 'Teddy'

reads (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/computed_macros.ts:732

import { reads } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computed property which creates a one way computed property to the original value for property.

This is a more semantically meaningful alias of the oneWay computed macro, whose name is somewhat ambiguous as to which direction the data flows.

setDiff (setAProperty, setBProperty) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:910

import { setDiff } from '@ember/object/computed';

setAProperty: String
setBProperty: String
returns: ComputedProperty; computes a new array with all the items from the first dependent array that are not in the second dependent array

A computed property which returns a new array with all the properties from the first dependent array that are not in the second dependent array.

Example:

        
          
              
              import { set } from '@ember/object';
import { setDiff } from '@ember/object/computed';

class Hamster {
  constructor(likes, fruits) {
    set(this, 'likes', likes);
    set(this, 'fruits', fruits);
  }

  @setDiff('likes', 'fruits') wants;
}

let hamster = new Hamster(
  [
    'banana',
    'grape',
    'kale'
  ],
  [
    'grape',
    'kale',
  ]
);

hamster.wants; // ['banana']
            

        
      

sort (itemsKey, sortDefinitionOrDependentKeys, sortDefinition) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:1035

import { sort } from '@ember/object/computed';

itemsKey: String
sortDefinitionOrDependentKeys: String|Function|Array; The key of the sort definition (an array of sort properties), the sort function, or an array of additional dependent keys
sortDefinition: Function?; the sort function (when used with additional dependent keys)
returns: ComputedProperty; computes a new sorted array based on the sort property array or callback function

A computed property which returns a new array with all the properties from the first dependent array sorted based on a property or sort function. The sort macro can be used in two different ways:

By providing a sort callback function
By providing an array of keys to sort the array

In the first form, the callback method you provide should have the following signature:

        
              function sortCallback(itemA, itemB);

itemA the first item to compare.
itemB the second item to compare.

This function should return negative number (e.g. -1) when itemA should come before itemB. It should return positive number (e.g. 1) when itemA should come after itemB. If the itemA and itemB are equal this function should return 0.

Therefore, if this function is comparing some numeric values, simple itemA - itemB or itemA.get( 'foo' ) - itemB.get( 'foo' ) can be used instead of series of if.

Example:

        
          
              
              import { set } from '@ember/object';
import { sort } from '@ember/object/computed';

class ToDoList {
  constructor(todos) {
    set(this, 'todos', todos);
  }

  // using a custom sort function
  @sort('todos', function(a, b){
    if (a.priority > b.priority) {
      return 1;
    } else if (a.priority < b.priority) {
      return -1;
    }

    return 0;
  })
  priorityTodos;
}

let todoList = new ToDoList([
  { name: 'Unit Test', priority: 2 },
  { name: 'Documentation', priority: 3 },
  { name: 'Release', priority: 1 }
]);

todoList.priorityTodos; // [{ name:'Release', priority:1 }, { name:'Unit Test', priority:2 }, { name:'Documentation', priority:3 }]
            

        
      

You can also optionally pass an array of additional dependent keys as the second parameter, if your sort function is dependent on additional values that could changes:

        
          
              
              import EmberObject, { set } from '@ember/object';
import { sort } from '@ember/object/computed';

class ToDoList {
  sortKey = 'priority';

  constructor(todos) {
    set(this, 'todos', todos);
  }

  // using a custom sort function
  @sort('todos', ['sortKey'], function(a, b){
    if (a[this.sortKey] > b[this.sortKey]) {
      return 1;
    } else if (a[this.sortKey] < b[this.sortKey]) {
      return -1;
    }

    return 0;
  })
  sortedTodos;
});

let todoList = new ToDoList([
  { name: 'Unit Test', priority: 2 },
  { name: 'Documentation', priority: 3 },
  { name: 'Release', priority: 1 }
]);

todoList.priorityTodos; // [{ name:'Release', priority:1 }, { name:'Unit Test', priority:2 }, { name:'Documentation', priority:3 }]
            

        
      

In the second form, you should provide the key of the array of sort values as the second parameter:

        
          
              
              import { set } from '@ember/object';
import { sort } from '@ember/object/computed';

class ToDoList {
  constructor(todos) {
    set(this, 'todos', todos);
  }

  // using standard ascending sort
  todosSorting = ['name'];
  @sort('todos', 'todosSorting') sortedTodos;

  // using descending sort
  todosSortingDesc = ['name:desc'];
  @sort('todos', 'todosSortingDesc') sortedTodosDesc;
}

let todoList = new ToDoList([
  { name: 'Unit Test', priority: 2 },
  { name: 'Documentation', priority: 3 },
  { name: 'Release', priority: 1 }
]);

todoList.sortedTodos; // [{ name:'Documentation', priority:3 }, { name:'Release', priority:1 }, { name:'Unit Test', priority:2 }]
todoList.sortedTodosDesc; // [{ name:'Unit Test', priority:2 }, { name:'Release', priority:1 }, { name:'Documentation', priority:3 }]
            

        
      

sum (dependentKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:76

Available since v1.4.0

import { sum } from '@ember/object/computed';

dependentKey: String
returns: ComputedProperty; computes the sum of all values in the dependentKey's array

A computed property that returns the sum of the values in the dependent array.

Example:

        
              import { sum } from '@ember/object/computed';

class Invoice {
  lineItems = [1.00, 2.50, 9.99];

  @sum('lineItems') total;
}

let invoice = new Invoice();

invoice.total; // 13.49

union (propertyKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:782

import { union } from '@ember/object/computed';

propertyKey: String
returns: ComputedProperty; computes a new array with all the unique elements from one or more dependent arrays.

A computed property which returns a new array with all the unique elements from one or more dependent arrays.

Example:

        
          
              
              import { set } from '@ember/object';
import { union } from '@ember/object/computed';

class Hamster {
  constructor(fruits, vegetables) {
    set(this, 'fruits', fruits);
    set(this, 'vegetables', vegetables);
  }

  @union('fruits', 'vegetables') uniqueFruits;
});

let hamster = new, Hamster(
  [
    'banana',
    'grape',
    'kale',
    'banana',
    'tomato'
  ],
  [
    'tomato',
    'carrot',
    'lettuce'
  ]
);

hamster.uniqueFruits; // ['banana', 'grape', 'kale', 'tomato', 'carrot', 'lettuce']
            

        
      

uniq (propertyKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:657

import { uniq } from '@ember/object/computed';

propertyKey: String
returns: ComputedProperty; computes a new array with all the unique elements from the dependent array

A computed property which returns a new array with all the unique elements from one or more dependent arrays.

Example:

        
              import { set } from '@ember/object';
import { uniq } from '@ember/object/computed';

class Hamster {
  constructor(fruits) {
    set(this, 'fruits', fruits);
  }

  @uniq('fruits') uniqueFruits;
}

let hamster = new Hamster([
  'banana',
  'grape',
  'kale',
  'banana'
]);

hamster.uniqueFruits; // ['banana', 'grape', 'kale']

uniqBy (dependentKey, propertyKey) ComputedProperty public

Module: @ember/object

Defined in packages/@ember/object/lib/computed/reduce_computed_macros.ts:728

import { uniqBy } from '@ember/object/computed';

dependentKey: String
propertyKey: String
returns: ComputedProperty; computes a new array with all the unique elements from the dependent array

A computed property which returns a new array with all the unique elements from an array, with uniqueness determined by specific key.

Example:

        
              import { set } from '@ember/object';
import { uniqBy } from '@ember/object/computed';

class Hamster {
  constructor(fruits) {
    set(this, 'fruits', fruits);
  }

  @uniqBy('fruits', 'id') uniqueFruits;
}

let hamster = new Hamster([
  { id: 1, 'banana' },
  { id: 2, 'grape' },
  { id: 3, 'peach' },
  { id: 1, 'banana' }
]);

hamster.uniqueFruits; // [ { id: 1, 'banana' }, { id: 2, 'grape' }, { id: 3, 'peach' }]

Class @ember/object/computed

alias (dependentKey) ComputedProperty public

and (dependentKey) ComputedProperty public

bool (dependentKey) ComputedProperty public

collect (dependentKey) ComputedProperty public

deprecatingAlias (dependentKey, options) ComputedProperty public

empty (dependentKey) ComputedProperty public

equal (dependentKey, value) ComputedProperty public

expandProperties (pattern, callback) public

filter (dependentKey, additionalDependentKeys, callback) ComputedProperty public

filterBy (dependentKey, propertyKey, value) ComputedProperty public

gt (dependentKey, value) ComputedProperty public

gte (dependentKey, value) ComputedProperty public

intersect (propertyKey) ComputedProperty public

lt (dependentKey, value) ComputedProperty public

lte (dependentKey, value) ComputedProperty public

map (dependentKey, additionalDependentKeys, callback) ComputedProperty public

mapBy (dependentKey, propertyKey) ComputedProperty public

match (dependentKey, regexp) ComputedProperty public

max (dependentKey) ComputedProperty public

min (dependentKey) ComputedProperty public

none (dependentKey) ComputedProperty public

not (dependentKey) ComputedProperty public

notEmpty (dependentKey) ComputedProperty public

oneWay (dependentKey) ComputedProperty public

or (dependentKey) ComputedProperty public

readOnly (dependentKey) ComputedProperty public

reads (dependentKey) ComputedProperty public

setDiff (setAProperty, setBProperty) ComputedProperty public

sort (itemsKey, sortDefinitionOrDependentKeys, sortDefinition) ComputedProperty public

sum (dependentKey) ComputedProperty public

union (propertyKey) ComputedProperty public

uniq (propertyKey) ComputedProperty public

uniqBy (dependentKey, propertyKey) ComputedProperty public