Map to Array in JavaScript
Last Updated :
29 Jun, 2023
In this article, we will convert a Map object to an Array in JavaScript. A Map is a collection of key-value pairs linked with each other. The following are the approaches to Map to Array conversion:
Methods to convert Map to Array
Using the Spread operator(...) and map() method, we can take each entry and convert it into an array of key-value pairs.
Syntax:
let Array = [...value];
// Arrow function
Array.map((e) => e);
Array.map((e, i) => {i,e});
Example: This example illustrates the implementation of the Spread Operator (...) Method and Array map() Method.
JavaScript
const mapObj = new Map();
mapObj.set(1, 'abc');
mapObj.set(2, 'xyz');
mapObj.set(3, 'pqr');
// Return the map
console.log(mapObj);
let arr = [...mapObj].map((e) => e)
// Return the array
console.log(arr);
OutputMap(3) { 1 => 'abc', 2 => 'xyz', 3 => 'pqr' }
[ [ 1, 'abc' ], [ 2, 'xyz' ], [ 3, 'pqr' ] ]
Approach 2: Using Array.from() Method
The Array.from() Method returns a new instance of an array from the object provided in the arguments.
Syntax:
Array.from(object, mapFunction, thisValue);
Example: In this example, we will pass a map object and a function into Array.from() Method to convert it into an array.
JavaScript
const mapObj = new Map();
mapObj.set(1, 'abc');
mapObj.set(2, 'xyz');
mapObj.set(3, 'pqr');
// Return the map
console.log(mapObj);
// Return the array
let arr = Array.from(mapObj);
console.log(arr);
OutputMap(3) { 1 => 'abc', 2 => 'xyz', 3 => 'pqr' }
[ [ 1, 'abc' ], [ 2, 'xyz' ], [ 3, 'pqr' ] ]
JavaScript map.forEach() method is used to iterate the map object and execute the callback function provided in the arguments.
Syntax:
mymap.forEach();
Example: This example illustrates the implementation of the map.forEach() Method.
JavaScript
const mapObj = new Map();
mapObj.set(1, 'abc');
mapObj.set(2, 'xyz');
mapObj.set(3, 'pqr');
// Return the map
console.log(mapObj);
const arr = [];
mapObj.forEach(
(value, key) => arr.push(
{ key, value }));
// Return the array
console.log(arr);
OutputMap(3) { 1 => 'abc', 2 => 'xyz', 3 => 'pqr' }
[
{ key: 1, value: 'abc' },
{ key: 2, value: 'xyz' },
{ key: 3, value: 'pqr' }
]
There are many inbuilt JavaScript methods that can be used to transform data from one data type to another. Above mentioned are a few of those that can be easily implemented to convert the Map object to an array.
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