javascript check if map contains key code example

Example 1: javascript does key exist

var person={"name":"Billy","age":20}
person.hasOwnProperty("name"); // true
person.hasOwnProperty("sex"); // false

Example 2: javascript hashtable contains key

if (obj.hasOwnProperty("key1")) {
  ...
}

Example 3: js check if map contains key

const map1 = new Map();
map1.set('bar', 'foo');

console.log(map1.has('bar'));
// expected output: true

console.log(map1.has('baz'));
// expected output: false