Convert object to List C#

Object.fromEntries[]

The Object.fromEntries[] method transforms a list of key-value pairs into an object.

Syntax

Object.fromEntries[iterable];

Parameters

iterable

An iterable such as Array or Map or other objects implementing the iterable protocol.

Return value

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

Description

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 @@iterator method, that returns an iterator object, that produces a two element array-like object, whose first element is a value that will be used as a property key, and whose second element is the value to associate with that property key.

Object.fromEntries[] performs the reverse of Object.entries[].

Examples

Converting a Map to an Object

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 }

Converting an Array to an Object

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" }

Object transformations

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 }

Specifications

Specification
ECMAScript Language Specification [ECMAScript]
# sec-object.fromentries

Browser compatibility

BCD tables only load in the browser

See also

  • A polyfill of Object.fromEntries is available in core-js
  • Object.entries[]
  • Object.keys[]
  • Object.values[]
  • Map.prototype.entries[]
  • Map.prototype.keys[]
  • Map.prototype.values[]

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