JavaScript Proxy/handler Reference

JavaScript WeakMap Reference

Last Updated : 18 Apr, 2025

JavaScript WeakMap object in JavaScript is used to store the collection of objects (key-value pairs) in which keys are weakly referenced. The major difference between a WeakSet with a set is that a WeakSet is a collection of objects and not values of some particular type.

Syntax:

WeakMap.function();

Example: Below is the example of weakMap.get() method.

JavaScript

function gfg() {
    const weakmap1 = new WeakMap();
    const key1 = {};
    weakmap1.set(key1, 12);
    console.log(weakmap1.get(key1));
}
gfg();

Output:

The complete list of JavaScript WeakMap is listed below:

JavaScript WeakMap Constructor: A constructor gets called when an object is created using the new keyword.

Constructor	Description
weakMap()	A constructor gets called when an object is created using the new keyword.

JavaScript WeakMap Properties: A JavaScript property is a member of an object that associates a key with a value.

Instance Properties: If the property is called on the instance of a WeakMap then it is called instance property.

Instance Property	Description
constructor	It is used to return the constructor function of WeakMap

JavaScript WeakMap Methods: JavaScript methods are actions that can be performed on objects.

Instance Method: If the method is called on an instance of a WeakMap then it is called an instance method.

Instance Methods	Description
delete()	Delete a particular element from an object WeakMap.
get()	Return a particular element from an object WeakMap.that
has()	Return a boolean value that indicates whether an element with a particular key presents in the weakmap object or not.
set()	Set a new element with a particular key and value to a WeakMap object.

JavaScript Proxy/handler Reference

kartik

Improve

Article Tags :

Similar Reads

JavaScript WeakSet Reference

JavaScript WeakSet is used to store a collection of objects. It adapts the same properties as that of a set i.e. does not store duplicates. The major difference between WeakSet and a set is that a WeakSet is a collection of objects and not values of some particular type. Syntax: weakSet.function();E

JavaScript WeakMap

A WeakMap in JavaScript is a collection of key-value pairs where the keys are objects, and the values can be any arbitrary value. Unlike regular maps, WeakMap keys are weakly referenced, meaning they don't prevent garbage collection. The keys in a WeakMap can be automatically removed when no longer

JavaScript weakMap set() Method

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 "v

JavaScript weakMap get() Method

The Javascript weakMap.get() is an inbuilt function in JavaScript that is used to return a particular element from an object WeakMap. Syntax: weakMap.get(key);Parameters: It accepts a parameter "key" which is the key of the element which is going to be returned from the object weakmap. Return values

JavaScript weakMap has() Method

The Javascript weakMap.has() is an inbuilt function in JavaScript that is used to return a boolean value which indicates whether an element with a particular key is present in the weakmap object or not. Syntax: weakMap.has(key);Parameters: It accepts a parameter 'key' which is the key of the element

JavaScript weakMap delete() Method

The weakMap.delete() is an inbuilt function in JavaScript which is used to delete a particular element from an object WeakMap. Syntax: weakMap.delete(key); Parameters: It accepts a parameter "key" which is the key of the element which is going to be deleted from the object weakMap. Return values: It

JavaScript WeakMap constructor Property

JavaScript WeakMap constructor property is used to return the WeakMap constructor function for the object. The function returned by this property is just the reference, not the actual WeakMap. It is an object property of JavaScript and can be used with Strings, Numbers, etc. Syntax: weakset.construc

How to understand WeakMap in JavaScript ?

The WeakMap object stores key/value pairs. The keys should be objects, and also the value may be anything. In JavaScript, a map API may be engineered with 2 arrays, one for keys and one for values that are shared by the four API functions. Setting parts on this map would entail at the same time inse

JavaScript WeakSet

A WeakSet in JavaScript is a collection of unique objects where the values are weakly referenced. It works similarly to a Set, but the objects stored in a WeakSet can be garbage-collected when no longer in use. A WeakSet can only store objects, not primitive values like strings or numbers.Objects in

WeakSet vs WeakMap in JavaScript

In JavaScript, there are two types of references strong and weak. The WeakSet and WeakMap are called weak references. Since these are weak references they do not prevent garbage collection if they are the only reference to the object in the memory. These objects are rarely used but are useful when w