Set.prototype.clear()
  The clear() method removes all elements from a
  Set object.
Syntax
clear()
Return value
Examples
Using the clear() method
var mySet = new Set();
mySet.add(1);
mySet.add('foo');
mySet.size;       // 2
mySet.has('foo'); // true
mySet.clear();
mySet.size;       // 0
mySet.has('bar')  // false
Specifications
| Specification | 
|---|
| ECMAScript Language Specification # sec-set.prototype.clear | 
Browser compatibility
BCD tables only load in the browser