JavaScript weakMap set() Method

Last Updated : 11 Jul, 2025

The weakMap.set() is an inbuilt function in JavaScript which is used to set a new element with a particular key and value to a WeakMap object.

Syntax:

weakMap.set(key, value);

Parameters: It takes parameters "key" which is the key of the element which is to set to the WeakMap object and parameter "value" is the value of the element to set to the WeakMap object.

Return value: It returns the WeakMap object.

Below are examples of weakMap.set() method.

Example 1:

javascript

function gfg() {   const weakmap1 = new WeakMap();  const key1 = {};  const key2 = {};  const key3 = {};  weakmap1.set(key1, 'G');  weakmap1.set(key2, 'F');  weakmap1.set(key3, 'G');  document.write(weakmap1.get(key1)   +weakmap1.get(key2)  +weakmap1.get(key3)); }

Output:

GFG

Example 2:

javascript

// creating WeakMap() object const weakmap1 = new WeakMap(); // Creating some keys const key1 = {}; const key2 = {}; // Setting key and value to the object. weakmap1.set(key1, 'GeeksForGeeks'); weakmap1.set(key2, 'gfg'); // Returning the set values console.log(weakmap1.get(key1)); console.log(weakmap1.get(key2));

Output:

GeeksForGeeks gfg

Example 3:

javascript

// creating WeakMap() object const weakmap1 = new WeakMap(); // Creating some keys const key1 = {}; const key2 = {}; const key3 = {}; const key4 = {}; const key5 = {}; const key6 = {}; // Setting key and value to the object. weakmap1.set(key1, 'GeeksForGeeks'); weakmap1.set(key2, 'gfg'); weakmap1.set(key3, 'GfG is a cse portal'); weakmap1.set(key4, '12345'); weakmap1.set(key5, '@#$%'); weakmap1.set(key6, '1.34'); // Returning the set values console.log(weakmap1.get(key1)); console.log(weakmap1.get(key2)); console.log(weakmap1.get(key3)); console.log(weakmap1.get(key4)); console.log(weakmap1.get(key5)); console.log(weakmap1.get(key6));

Output:

GeeksForGeeks gfg GfG is a cse portal 12345 @#$% 1.34

Supported Browsers:

Google Chrome 36 and above
Edge 12 and above
Firefox 6 and above
Internet Explorer 11 and above
Opera 23 and above
Safari 8 and above

We have a complete list of Javascript weakMap methods, to check those please go through this JavaScript WeakMap Complete Reference article.

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.