javascript hashmap check if key exists code example

Example 1: javascript does key exist

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

Example 2: if key exists in hashmap java

Hash_Map.containsKey(key_element)

Example 3: check if a key exists in an object javascript

"key" in obj // true, regardless of the actual value