if key exists in dictionary javascript 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: how to check if a key exists in an object javascript
!("key" in obj) // true if "key" doesn't exist in object
!"key" in obj // ERROR! Equivalent to "false in obj"