JavaScript | weakSet.has() with Examples

The weakSet.has() is an inbuilt function in JavaScript which is used to return a boolean value indicating whether an object is present in a weakSet or not. The WeakSet object lets you store weakly held objects in a collection.
Syntax:

weakSet.has(A);

Parameters: It accepts the parameter “A” which is a value going to be checked whether it is present in the weakSet object or not.
Return Values: It returns boolean value true if the element is present otherwise it returns false.

JavaScript code to show the working of this function:
Code #1:

<script> 
  
   // Constructing a weakSet() object 
   const A = new WeakSet(); 
  
   // Constructing new objects 
   const object1 = {}; 
  
   // Adding the new object to the weakSet 
   A.add(object1); 
  
   // Checking whether the new object is present 
   // in the weakSet or not 
   document.write(A.has(object1) +"<br>"); 
  
</script> 

Output:

true

Here output is true because the object “object1” is present in the WeakSet() object.
Code #2:

<script> 
  
   // Constructing a weakSet() object 
   const A = new WeakSet(); 
  
   // Constructing new objects 
   const object1 = {}; 
  
   // Checking whether the new object is present 
   // in the weakSet or not 
   document.write(A.has(object1) +"<br>"); 
  
</script> 

Output:

false

Here output is false because the object “object1” is not present in the WeakSet() object.

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