WeakSet.prototype.add() - JavaScript 编辑

The add() method appends a new object to the end of a WeakSet object.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Syntax

ws.add(value);

Parameters

value

Required. The object to add to the WeakSet collection.

Return value

The WeakSet object.

Examples

Using add

var 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

Browser compatibility

BCD tables only load in the browser

See also

• WeakSet
• WeakSet.prototype.delete()
• WeakSet.prototype.has()