JavaScript Map set() Method Last Updated : 23 Jul, 2025 Comments Improve Suggest changes Like Article Like Report The JavaScript map.set() method is used to add key-value pairs to a Map object. It can also be used to update the value of an existing key. Each value must have a unique key so that they get mapped correctly.Syntax:GFGmap.set(key, value);Parameters:This method accepts two parameters as mentioned above and described below:Key: This is the key of the item that has to be added or updated in the Map.Value: This is the value of the item that has to be added or updated in the Map.Example 1: JavaScript let GFGMap = new Map(); // Adding a key value pair GFGMap.set(1, "India"); // Getting the value by key console.log(GFGMap.get(1)); // Updating the existing value GFGMap.set(1, "England"); // Getting the value back console.log(GFGMap.get(1)); Output:IndiaEnglandExample 2: Using set() with chaining JavaScript let myMap = new Map(); // Adding key value pair with chaining myMap.set(1, "Rohan").set(2, "Sohan").set(3, "Trojan"); // Getting the values back console.log(myMap.get(1)); console.log(myMap.get(2)); console.log(myMap.get(3)); Output:RohanSohanTrojanSupported Browsers:Chrome 38 Edge 12 Firefox 13Opera 25Safari 8 Comment More info H hritikrommie Follow Improve Article Tags : JavaScript Web Technologies JavaScript-Methods Explore JavaScript BasicsIntroduction to JavaScript4 min readVariables and Datatypes in JavaScript6 min readJavaScript Operators5 min readControl Statements in JavaScript4 min readArray & StringJavaScript Arrays7 min readJavaScript Array Methods7 min readJavaScript Strings6 min readJavaScript String Methods9 min readFunction & ObjectFunctions in JavaScript5 min readJavaScript Function Expression3 min readFunction Overloading in JavaScript4 min readObjects in Javascript4 min readJavaScript Object Constructors4 min readOOPObject Oriented Programming in JavaScript3 min readClasses and Objects in JavaScript4 min readWhat Are Access Modifiers In JavaScript ?5 min readJavaScript Constructor Method7 min readAsynchronous JavaScriptAsynchronous JavaScript2 min readJavaScript Callbacks4 min readJavaScript Promise4 min readEvent Loop in JavaScript4 min readAsync and Await in JavaScript2 min readException HandlingJavascript Error and Exceptional Handling6 min readJavaScript Errors Throw and Try to Catch2 min readHow to create custom errors in JavaScript ?2 min readJavaScript TypeError - Invalid Array.prototype.sort argument1 min readDOMHTML DOM (Document Object Model)9 min readHow to select DOM Elements in JavaScript ?3 min readJavaScript Custom Events4 min readJavaScript addEventListener() with Examples9 min readAdvanced TopicsClosure in JavaScript4 min readJavaScript Hoisting6 min readJavascript Scope3 min readJavaScript Higher Order Functions7 min readDebugging in JavaScript4 min read Like