JavaScript weakSet add() Method Last Updated : 11 Jul, 2025 Suggest changes Share Like Article Like Report Javascript weakSet.add() is used to add an object at the end of the object WeakSet. The WeakSet object lets you store weakly held objects in a collection. Syntax: weakSet.add(A);Parameters: This method accepts a single parameter value. value: This value will be added to the weakset object. Return Values: It returns the newly added weakset object. Below are examples of weakSet.add() method: Example 1: This is a basic example of weakset.add() method in javascript. javascript function gfg() { const weakset = new WeakSet(); const object1 = {}; weakset.add(object1); console.log(weakset.has(object1)); } gfg(); OutputtrueExample 2: Here the output is true because the newly created objects have been set to the end of the weakSet() object. javascript // Constructing a weakset object const weakset = new WeakSet(); // Constructing a new object object1 const object1 = {}; const object2 = {}; const object3 = {}; const object4 = {}; // Adding the object1 at the end of the weakset object. weakset.add(object1); weakset.add(object2); weakset.add(object3); weakset.add(object4); // Printing either object has been added or not console.log(weakset.has(object1)); console.log(weakset.has(object2)); console.log(weakset.has(object3)); console.log(weakset.has(object4)); Outputtrue true true trueExample 3: Here the output is false because the newly created objects have not been set to the end of the weakSet() object. javascript // Constructing a weakset object const weakset = new WeakSet(); // Constructing a new object object1 const object1 = {}; const object2 = {}; const object3 = {}; const object4 = {}; // Printing either object has been added or not console.log(weakset.has(object1)); console.log(weakset.has(object2)); console.log(weakset.has(object3)); console.log(weakset.has(object4)); Outputfalse false false falseSupported Browsers:Google Chrome 36 and aboveFirefox 34 and aboveApple Safari 9 and aboveOpera 23 and aboveEdge 12 and aboveWe have a complete list of Javascript WeakSet methods, to check those please go through Javascript WeakSet Complete reference article. S ShivamKD Follow Article Tags : JavaScript Web Technologies JavaScript-WeakSet 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 Strings5 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 readScope of Variables in JavaScript3 min readJavaScript Higher Order Functions7 min readDebugging in JavaScript4 min read My Profile ${profileImgHtml} My Profile Edit Profile My Courses Join Community Transactions Logout Like