WeakMap.prototype.has()
The has() method returns a boolean indicating whether an
element with the specified key exists in the WeakMap object or not.
Syntax
has(key)
Parameters
key- : Required. The key of the element to test for presence in the
WeakMapobject.
- : Required. The key of the element to test for presence in the
Return value
- Boolean
- : Returns
trueif an element with the specified key exists in theWeakMapobject; otherwisefalse.
- : Returns