JavaScript Map

Map is a collection of key-value pairs, where the key can be any data type.

Map will remember the original insertion order of keys.

How to create Map

You can create JavaScript Map in the following ways:

1. Pass an array to new Map().
2. Create a Map and use Map.set().

new Map() method

You can pass an array to new Map() Constructor to create Map:

Instance

// Create a Map
const fruits = new Map([
  ["apples", 500],
  ["bananas", 300],
  
]

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set() method

You can use set() Method to add elements to Map:

Instance

// Create a Map
const fruits = new Map();
// Set Map value
fruits.set("apples", 500);
fruits.set("bananas", 300);
fruits.set("oranges", 200);

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set() The method can also be used to change the existing Map value:

Instance

fruits.set("apples", 200);

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get() method

get() Method to get the value of the key in Map:

Instance

fruits.get("apples");    // Returns 500

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Map is an object

typeof Returns object:

Instance

// Returns object:
typeof fruits;

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instanceof Map Returns true:

Instance

// Returns true:
fruits instanceof Map;

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The difference between JavaScript objects and Map

The following is the difference between JavaScript objects and Map:

Complete Map Reference Manual

For a complete reference, please visit our:JavaScript Map Reference Manual.

This manual includes descriptions and examples of all Map properties and methods.

Browser Support

Map is ES6 Features(JavaScript 2015).

Starting from June 2017, all modern browsers support ES6:

Internet Explorer does not support Map.