Object.fromEntries()

iterable

An iterable, such as an Array or Map, containing a list of objects. Each object should have two properties:

0

A string or symbol representing the property key.

1

The property value.

Typically, this object is implemented as a two-element array, with the first element being the property key and the second element being the property value.

A new object whose properties are given by the entries of the iterable.

The Object.fromEntries() method takes a list of key-value pairs and returns a new object whose properties are given by those entries. The iterable argument is expected to be an object that implements an [Symbol.iterator]() method. The method returns an iterator object that produces two-element array-like objects. The first element is a value that will be used as a property key, and the second element is the value to associate with that property key.

Object.fromEntries() performs the reverse of Object.entries(), except that Object.entries() only returns string-keyed properties, while Object.fromEntries() can also create symbol-keyed properties.

With Object.fromEntries, you can convert from Map to Object:

const map = new Map([ ["foo", "bar"], ["baz", 42], ]); const obj = Object.fromEntries(map); console.log(obj); // { foo: "bar", baz: 42 } 

With Object.fromEntries, you can convert from Array to Object:

const arr = [ ["0", "a"], ["1", "b"], ["2", "c"], ]; const obj = Object.fromEntries(arr); console.log(obj); // { 0: "a", 1: "b", 2: "c" } 

With Object.fromEntries, its reverse method Object.entries(), and array manipulation methods, you are able to transform objects like this:

const object1 = { a: 1, b: 2, c: 3 }; const object2 = Object.fromEntries( Object.entries(object1).map(([key, val]) => [key, val * 2]), ); console.log(object2); // { a: 2, b: 4, c: 6 } 

• Polyfill of Object.fromEntries in core-js
• es-shims polyfill of Object.fromEntries
• Object.entries()
• Object.keys()
• Object.values()
• Object.prototype.propertyIsEnumerable()
• Object.create()
• Map.prototype.entries()
• Map.prototype.keys()
• Map.prototype.values()