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JavaScript Set add() method

The JavaScript Set add() method is used to add a new object to the end of a WeakSet object.

Syntax

The add() method is represented by the following syntax:

Parameter

value - It represents the object to be added.

Return

The WeakSet object.

JavaScript Set add() method example

Here, we will understand add() method through various examples.

Example 1

Let's see an example to add object to WeakSet object.

<script>
var ws = new WeakSet();
var obj1={};
var obj2={};
ws.add(obj1);
ws.add(obj2);
//Let's check whether the WeakSet object contains the added object
document.writeln(ws.has(obj1)+"<br>");
document.writeln(ws.has(obj2));
</script>

Test it Now

Output:

true
true

Example 2

In this example, we will see whether we add the objects to WeakSet object without initializing them.

<script>
var ws = new WeakSet();
try
  {
ws.add(obj);
document.writeln(ws.has(obj));    
  }
catch(error)
  {
    document.writeln(error);
  }
</script>

Test it Now

Output:

ReferenceError: obj is not defined

Next TopicWeakSet delete() Method

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