javascript is set contains code example

Example 1: javascript check if set contains

var mySet = new Set();
mySet.add('foo');

mySet.has('foo');  // returns true
mySet.has('bar');  // returns false

var set1 = new Set();
var obj1 = {'key1': 1};
set1.add(obj1);

set1.has(obj1);        // returns true
set1.has({'key1': 1}); // returns false because they are different object references
set1.add({'key1': 1}); // now set1 contains 2 entries

Example 2: set.contains in javascript

const set = new Set();

set.add(1);
set.add(2);
set.add(3);

console.log(set.has(2));  //true
console.log(set.has(4)); //false