JavaScript Array from() Method

The Array.from() method is used to create a new array from any iterables like array, objects, and strings.

const a = Array.from("GeeksforGeeks");
console.log(a);

[
  'G', 'e', 'e', 'k',
  's', 'f', 'o', 'r',
  'G', 'e', 'e', 'k',
  's'
]

 Syntax

Array.from(object, mapFunction, thisValue);

Parameters

• object: This parameter holds that object that will convert into an array
• mapFunction: This parameter is optional and used to call on each item of the array.
• thisValue: This parameter is optional, it holds the context to be passed as this is to be used while executing the mapFunction. If the context is passed, it will be used like this for each invocation of the callback function, otherwise undefined is used as default.

Return value

It returns a new array from the iterable passed as argument.

We have a complete list of Javascript Array methods, to check those please go through this Javascript Array Complete reference article.

Creating Array from Set

We can use Array.from() method to create or convert the given set to the array.

const s = new Set([10, 20, 30]);
const a = Array.from(s);
console.log(a);

[ 10, 20, 30 ]

Creating Array from Object

It can create array from the keys, values and also from each entry of the object.

const obj = { a: 10, b: 20, c : 30, d : 40, e : 50 };

const a1 = Array.from(Object.keys(obj));
const a2 = Array.from(Object.values(obj));
const a3 = Array.from(Object.entries(obj));

console.log(a1);
console.log(a2);
console.log(a3);

[ 'a', 'b', 'c', 'd', 'e' ]
[ 10, 20, 30, 40, 50 ]
[ [ 'a', 10 ], [ 'b', 20 ], [ 'c', 30 ], [ 'd', 40 ], [ 'e', 50 ] ]

We have a Cheat Sheet on Javascript where we covered all the important topics of Javascript to check those please go through Javascript Cheat Sheet-A Basic guide to JavaScript.