Class EmberArray

Adds an array observer to the receiving array. The array observer object normally must implement two methods:

• willChange(observedObj, start, removeCount, addCount) - This method will be called just before the array is modified.
• didChange(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.

The any() method executes the callback function once for each element present in the array until it finds the one where callback returns a truthy value (i.e. true). If such an element is found, any() immediately returns true. Otherwise, any() returns false.

function(item, index, array);

• item is the current item in the iteration.
• index is the current index in the iteration.
• array is the array 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. It can be a good way to give your iterator function access to an object in cases where an ES6 arrow function would not be appropriate.

Usage Example:

let includesManager = people.any(this.findPersonInManagersList, this);

let includesStockHolder = people.any(person => {
  return this.findPersonInStockHoldersList(person)
});

if (includesManager || includesStockHolder) {
  Paychecks.addBiggerBonus();
}

If you are implementing an object that supports EmberArray, 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.

let arr = [1, 2, 3, 4, 5];

arr.copyWithin(-2); // [1, 2, 3, 1, 2]
// arr.lastObject = 5
arr.arrayContentDidChange(3, 2, 2);
// arr.lastObject = 2

If you are implementing an object that supports EmberArray, 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.

import Component from '@ember/component';
import EmberObject from '@ember/object';

const Post = EmberObject.extend({
  body: '',
  save() {}
})

export default Component.extend({
  attemptsToModify: 0,
  successfulModifications: 0,
  posts: null,

  init() {
    this._super(...arguments);

    this.posts = [1, 2, 3].map(i => Post.create({ body: i }));
    this.posts.addArrayObserver(this, {
      willChange() {
        this.incrementProperty('attemptsToModify');
      },
      didChange() {
        this.incrementProperty('successfulModifications');
      }
    });
  },

  actions: {
    editPost(post, newContent) {
      let oldContent = post.body,
          postIndex = this.posts.indexOf(post);

      this.posts.arrayContentWillChange(postIndex, 0, 0); // attemptsToModify = 1
      post.set('body', newContent);

      post.save()
        .then(response => {
          this.posts.arrayContentDidChange(postIndex, 0, 0); // successfulModifications = 1
        })
        .catch(error => {
          post.set('body', oldContent);
        })
    }
  }
});

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

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

Returns true if the passed function returns true for every item in the enumeration. This corresponds with the Array.prototype.every() method defined in ES5.

The callback method should have the following signature:

function(item, index, array);

• item is the current item in the iteration.
• index is the current index in the iteration.
• array is the array itself.

All params are optional. The method should return 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.

Usage example:

function isAdult(person) {
  return person.age > 18;
};

const people = Ember.A([{ name: 'John', age: 24 }, { name: 'Joan', age: 45 }]);
const areAllAdults = people.every(isAdult);

Returns a new array with all of the items in the enumeration that the provided callback function returns true for. This method corresponds to Array.prototype.filter().

The callback method should have the following signature:

function(item, index, array);

• item is the current item in the iteration.
• index is the current index in the iteration.
• array is the array itself.

All parameters are optional. The function should return true to include the item in the results, and false otherwise.

Example:

function isAdult(person) {
  return person.age > 18;
};

let people = Ember.A([{ name: 'John', age: 14 }, { name: 'Joan', age: 45 }]);

people.filter(isAdult); // returns [{ name: 'Joan', age: 45 }];

Note that in addition to a callback, you can 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. For example:

function isAdultAndEngineer(person) {
  return person.age > 18 && this.engineering;
}

class AdultsCollection {
  engineering = false;

  constructor(opts = {}) {
    super(...arguments);

    this.engineering = opts.engineering;
    this.people = Ember.A([{ name: 'John', age: 14 }, { name: 'Joan', age: 45 }]);
  }
}

let collection = new AdultsCollection({ engineering: true });
collection.people.filter(isAdultAndEngineer, { target: collection });

Filters the array by the property and an optional value. If a value is given, it returns the items that have said value for the property. If not, it returns all the items that have a truthy value for the property.

Example Usage:

let things = Ember.A([{ food: 'apple', isFruit: true }, { food: 'beans', isFruit: false }]);

things.filterBy('food', 'beans'); // [{ food: 'beans', isFruit: false }]
things.filterBy('isFruit'); // [{ food: 'apple', isFruit: true }]

Returns the first item in the array for which the callback returns true. This method is similar to the find() method defined in ECMAScript 2015.

The callback method you provide should have the following signature (all parameters are optional):

function(item, index, array);

• item is the current item in the iteration.
• index is the current index in the iteration.
• array is the array 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.

Example Usage:

let users = [
  { id: 1, name: 'Yehuda' },
  { id: 2, name: 'Tom' },
  { id: 3, name: 'Melanie' },
  { id: 4, name: 'Leah' }
];

users.find((user) => user.name == 'Tom'); // [{ id: 2, name: 'Tom' }]
users.find(({ id }) => id == 3); // [{ id: 3, name: 'Melanie' }]

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.

Usage Example:

let users = [
  { id: 1, name: 'Yehuda', isTom: false },
  { id: 2, name: 'Tom', isTom: true },
  { id: 3, name: 'Melanie', isTom: false },
  { id: 4, name: 'Leah', isTom: false }
];

users.findBy('id', 4); // { id: 4, name: 'Leah', isTom: false }
users.findBy('name', 'Melanie'); // { id: 3, name: 'Melanie', isTom: false }
users.findBy('isTom'); // { id: 2, name: 'Tom', isTom: true }

Iterates through the array, 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, array);

• item is the current item in the iteration.
• index is the current index in the iteration.
• array is the array 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.

Example Usage:

let foods = [
  { name: 'apple', eaten: false },
  { name: 'banana', eaten: false },
  { name: 'carrot', eaten: false }
];

foods.forEach((food) => food.eaten = true);

let output = '';
foods.forEach((item, index, array) =>
  output += `${index + 1}/${array.length} ${item.name}\n`;
);
console.log(output);
// 1/3 apple
// 2/3 banana
// 3/3 carrot

Alias for mapBy.

Returns the value of the named property on all items in the enumeration.

let people = [{name: 'Joe'}, {name: 'Matt'}];

people.getEach('name');
// ['Joe', 'Matt'];

people.getEach('nonexistentProperty');
// [undefined, undefined];

Used to determine if the array contains the passed object. Returns true if found, false otherwise.

The optional startAt argument can be used to pass a starting index to search from, effectively slicing the searchable portion of the array. If it's negative it will add the array length to the startAt value passed in as the index to search from. If less than or equal to -1 * array.length the entire array is searched.

This method has the same behavior of JavaScript's Array.includes.

[1, 2, 3].includes(2);     // true
[1, 2, 3].includes(4);     // false
[1, 2, 3].includes(3, 2);  // true
[1, 2, 3].includes(3, 3);  // false
[1, 2, 3].includes(3, -1); // true
[1, 2, 3].includes(1, -1); // false
[1, 2, 3].includes(1, -4); // true
[1, 2, NaN].includes(NaN); // true

Used to determine the passed object's first occurrence in the array. Returns the index if found, -1 if no match is found.

The optional startAt argument can be used to pass a starting index to search from, effectively slicing the searchable portion of the array. If it's negative it will add the array length to the startAt value passed in as the index to search from. If less than or equal to -1 * array.length the entire array is searched.

let arr = ['a', 'b', 'c', 'd', 'a'];

arr.indexOf('a');       //  0
arr.indexOf('z');       // -1
arr.indexOf('a', 2);    //  4
arr.indexOf('a', -1);   //  4, equivalent to indexOf('a', 4)
arr.indexOf('a', -100); //  0, searches entire array
arr.indexOf('b', 3);    // -1
arr.indexOf('a', 100);  // -1

let people = [{ name: 'Zoey' }, { name: 'Bob' }]
let newPerson = { name: 'Tom' };
people = [newPerson, ...people, newPerson];

people.indexOf(newPerson);     //  0
people.indexOf(newPerson, 1);  //  3
people.indexOf(newPerson, -4); //  0
people.indexOf(newPerson, 10); // -1

Invokes the named method on every object in the receiver that implements it. This method corresponds to the implementation in Prototype 1.6.

class Person {
  name = null;

  constructor(name) {
    this.name = name;
  }

  greet(prefix='Hello') {
    return `${prefix} ${this.name}`;
  }
}

let people = [new Person('Joe'), new Person('Matt')];

people.invoke('greet'); // ['Hello Joe', 'Hello Matt']
people.invoke('greet', 'Bonjour'); // ['Bonjour Joe', 'Bonjour Matt']

Returns true if the passed property resolves to the value of the second argument for any item in the array. This method is often simpler/faster than using a callback.

Example usage:

const food = [
  { food: 'apple', isFruit: true },
  { food: 'bread', isFruit: false },
  { food: 'banana', isFruit: true }
];

food.isAny('isFruit'); // true

Returns true if the passed property resolves to the value of the second argument for all items in the array. This method is often simpler/faster than using a callback.

Note that like the native Array.every, isEvery will return true when called on any empty array.

class Language {
  constructor(name, isProgrammingLanguage) {
    this.name = name;
    this.programmingLanguage = isProgrammingLanguage;
  }
}

const compiledLanguages = [
  new Language('Java', true),
  new Language('Go', true),
  new Language('Rust', true)
]

const languagesKnownByMe = [
  new Language('Javascript', true),
  new Language('English', false),
  new Language('Ruby', true)
]

compiledLanguages.isEvery('programmingLanguage'); // true
languagesKnownByMe.isEvery('programmingLanguage'); // false

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 greater than or equal to the length of the array, the search starts from the last position.
• If it's negative, it is taken as the offset from the end of the array i.e. startAt + array.length.
• If it's any other positive number, will search backwards from that index of the array.

Returns -1 if no match is found.

let 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('a', -3);   //  0
arr.lastIndexOf('b', 3);    //  1
arr.lastIndexOf('a', 100);  //  4

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, array);
let arr = [1, 2, 3, 4, 5, 6];

arr.map(element => element * element);
// [1, 4, 9, 16, 25, 36];

arr.map((element, index) => element + index);
// [1, 3, 5, 7, 9, 11];

• item is the current item in the iteration.
• index is the current index in the iteration.
• array is the array 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.

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

let people = [{name: 'Joe'}, {name: 'Matt'}];

people.mapBy('name');
// ['Joe', 'Matt'];

people.mapBy('unknownProperty');
// [undefined, undefined];

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 EmberArray. 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.

let 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

This returns the objects at the specified indexes, using objectAt.

let arr = ['a', 'b', 'c', 'd'];

arr.objectsAt([0, 1, 2]);  // ['a', 'b', 'c']
arr.objectsAt([2, 3, 4]);  // ['c', 'd', undefined]

This will combine the values of the array into a single value. It is a useful way to collect a summary value from an array. 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):

function(previousValue, item, index, array);

• 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.
• array is the array 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.

Example Usage:

  let numbers = [1, 2, 3, 4, 5];

  numbers.reduce(function(summation, current) {
    return summation + current;
  }); // 15 (1 + 2 + 3 + 4 + 5)

  numbers.reduce(function(summation, current) {
    return summation + current;
  }, -15); // 0 (-15 + 1 + 2 + 3 + 4 + 5)


  let binaryValues = [true, false, false];

  binaryValues.reduce(function(truthValue, current) {
    return truthValue && current;
  }); // false (true && false && false)

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, array);

• item is the current item in the iteration.
• index is the current index in the iteration
• array is the array 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.

Example Usage:

const food = [
  { food: 'apple', isFruit: true },
  { food: 'bread', isFruit: false },
  { food: 'banana', isFruit: true }
];
const nonFruits = food.reject(function(thing) {
  return thing.isFruit;
}); // [{food: 'bread', isFruit: false}]

Returns an array with the items that do not have truthy values for the provided key. You can pass an optional second argument with a target value to reject for the key. Otherwise this will reject objects where the provided property evaluates to false.

Example Usage:

  let food = [
    { name: "apple", isFruit: true },
    { name: "carrot", isFruit: false },
    { name: "bread", isFruit: false },
  ];
  food.rejectBy('isFruit'); // [{ name: "carrot", isFruit: false }, { name: "bread", isFruit: false }]
  food.rejectBy('name', 'carrot'); // [{ name: "apple", isFruit: true }}, { name: "bread", isFruit: false }]

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.

Sets the value on the named property for each member. This is more ergonomic than using other methods defined on this helper. If the object implements Observable, the value will be changed to set(), otherwise it will be set directly. null objects are skipped.

let people = [{name: 'Joe'}, {name: 'Matt'}];

people.setEach('zipCode', '10011');
// [{name: 'Joe', zipCode: '10011'}, {name: 'Matt', zipCode: '10011'}];

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.

let arr = ['red', 'green', 'blue'];

arr.slice(0);       // ['red', 'green', 'blue']
arr.slice(0, 2);    // ['red', 'green']
arr.slice(1, 100);  // ['green', 'blue']

Sorts the array by the keys specified in the argument.

You may provide multiple arguments to sort by multiple properties.

   let colors = [
 { name: 'red', weight: 500 },
 { name: 'green', weight: 600 },
 { name: 'blue', weight: 500 }
];

   colors.sortBy('name');
   // [{name: 'blue', weight: 500}, {name: 'green', weight: 600}, {name: 'red', weight: 500}]

   colors.sortBy('weight', 'name');
   // [{name: 'blue', weight: 500}, {name: 'red', weight: 500}, {name: 'green', weight: 600}]

Simply converts the object into a genuine array. The order is not guaranteed. Corresponds to the method implemented by Prototype.

Returns a new array that contains only unique values. The default implementation returns an array regardless of the receiver type.

let arr = ['a', 'a', 'b', 'b'];
arr.uniq();  // ['a', 'b']

This only works on primitive data types, e.g. Strings, Numbers, etc.

Returns a new array that contains only items containing a unique property value. The default implementation returns an array regardless of the receiver type.

let arr = [{ value: 'a' }, { value: 'a' }, { value: 'b' }, { value: 'b' }];
arr.uniqBy('value');  // [{ value: 'a' }, { value: 'b' }]

let arr = [2.2, 2.1, 3.2, 3.3];
arr.uniqBy(Math.floor);  // [2.2, 3.2];

Returns a new array that excludes the passed value. The default implementation returns an array regardless of the receiver type. If the receiver does not contain the value it returns the original array.

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