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 Latest Draft (ECMA-262) The definition of 'Object.entries' in that specification. |
Living Standard | Initial definition. |
ECMAScript 2017 (ECMA-262) The definition of 'Object.entries' in that specification. |
Standard |
Browser compatibility
Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|---|
Basic support | 54 | (Yes) | 47 (47) | No support | No support | 10.1 |
Feature | Android Webview | Chrome for Android | Edge | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|---|
Basic support | 54 | 54 | (Yes) | 47.0 (47) | No support | No support | No support |