Baseline Widely available
The has()
method of WeakMap
instances returns a boolean indicating whether an element with the specified key exists in this WeakMap
or not.
const weakmap1 = new WeakMap();
const object1 = {};
const object2 = {};
weakmap1.set(object1, "foo");
console.log(weakmap1.has(object1));
// Expected output: true
console.log(weakmap1.has(object2));
// Expected output: false
Syntax Parameters
key
The key of the element to test for presence in the WeakMap
object.
Returns true
if an element with the specified key exists in the WeakMap
object; otherwise false
. Always returns false
if key
is not an object or a non-registered symbol.
const wm = new WeakMap();
wm.set(window, "foo");
wm.has(window); // returns true
wm.has("baz"); // returns false
Specifications Browser compatibility See also
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4