WeakSet.prototype.add()
The add()
method appends a new object to the end of a
WeakSet
object.
Try it
Syntax
js
add(value)
Parameters
value
-
Must be either an object or a non-registered symbol. The value to add to the
WeakSet
collection.
Return value
The WeakSet
object.
Exceptions
TypeError
-
Thrown if
value
is not an object or a non-registered symbol.
Examples
Using add
js
const ws = new WeakSet();
ws.add(window); // add the window object to the WeakSet
ws.has(window); // true
// WeakSet only takes objects as arguments
ws.add(1);
// results in "TypeError: Invalid value used in weak set" in Chrome
// and "TypeError: 1 is not a non-null object" in Firefox
Specifications
Specification |
---|
ECMAScript Language Specification # sec-weakset.prototype.add |
Browser compatibility
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