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Object.entries

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The Object.entries() method returns an array of a given object's own enumerable property [key, value] pairs, in the same order as that provided by a for...in loop (the difference being that a for-in loop enumerates properties in the prototype chain as well).

Syntax

Object.entries(obj)

Parameters

obj
The object whose enumerable own property [key, value] pairs are to be returned.

Return value

An array of the given object's own enumerable property [key, value] pairs.

Description

Object.entries() returns an array whose elements are arrays corresponding to the enumerable property [key, value] pairs found directly upon object. The ordering of the properties is the same as that given by looping over the property values of the object manually.

Examples

var obj = { foo: 'bar', baz: 42 };
console.log(Object.entries(obj)); // [ ['foo', 'bar'], ['baz', 42] ]

// array like object
var obj = { 0: 'a', 1: 'b', 2: 'c' };
console.log(Object.entries(obj)); // [ ['0', 'a'], ['1', 'b'], ['2', 'c'] ]

// array like object with random key ordering
var an_obj = { 100: 'a', 2: 'b', 7: 'c' };
console.log(Object.entries(an_obj)); // [ ['2', 'b'], ['7', 'c'], ['100', 'a'] ]

// getFoo is property which isn't enumerable
var my_obj = Object.create({}, { getFoo: { value: function() { return this.foo; } } });
my_obj.foo = 'bar';
console.log(Object.entries(my_obj)); // [ ['foo', 'bar'] ]

// non-object argument will be coerced to an object
console.log(Object.entries('foo')); // [ ['0', 'f'], ['1', 'o'], ['2', 'o'] ]

// iterate through key-value gracefully
var obj = {a: 5, b: 7, c: 9};
for (var [key, value] of Object.entries(obj)) {
    console.log(key + ' ' + value); // "a 5", "b 7", "c 9"
}

// Or, using array extras...
Object.entries(obj).forEach(([key, value]) => {
    console.log(key + ' ' + value); // "a 5", "b 7", "c 9"     
});

Converting an Object to a Map

The new Map() constructor accepts an iterable of entries. With Object.entries, you can easily convert from Object to Map:

var obj = { foo: 'bar', baz: 42 }; 
var map = new Map(Object.entries(obj));
console.log(map); // Map { foo: "bar", baz: 42 }

Polyfill

To add compatible Object.entries support in older environments that do not natively support it, you can find a Polyfill in the tc39/proposal-object-values-entries or in the es-shims/Object.entries repositories.

Specifications

Specification Status Comment
ECMAScript 2017 Draft (ECMA-262)
The definition of 'Object.entries' in that specification.
Draft Initial definition.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 54 47 (47) No support No support No support [1]
Feature Android Webview Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support 54 54 47.0 (47) No support No support No support

[1] See bug 150131.

See also

© 2005–2017 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries