WeakMap.prototype.get()

The get() method returns a specified element from a WeakMap object.

Syntax

wm.get(key);

Parameters

key

Required. The key of the element to return from the WeakMap object.

Return value

Returns the element associated with the specified key or undefined if the key can't be found in the WeakMap object.

Examples

Using the get method

var wm = new WeakMap();
wm.set(window, "foo");

wm.get(window); // Returns "foo".
wm.get("baz");  // Returns undefined.

Specifications

Browser compatibility

Firefox-specific notes

• Prior to SpiderMonkey 38 (Firefox 38 / Thunderbird 38 / SeaMonkey 2.35), this method threw a TypeError when the key parameter was not an object. However, the latest ES6 standard specifies to return undefined instead. Furthermore, WeakMap.prototype.get accepted an optional second argument as a fallback value, which is not part of the standard. Both non-standard behaviors are removed in version 38 and higher (bug 1127827).

See also

• WeakMap
• WeakMap.set()
• WeakMap.has()