javascript dictionary check if key exists code example
Example 1: javascript does key exist
var person={"name":"Billy","age":20}
person.hasOwnProperty("name");
person.hasOwnProperty("sex");
Example 2: check if a key exists in an object javascript
"key" in obj
Example 3: js check if object key exists
var obj = { key: undefined };
obj["key"] !== undefined
Example 4: check if key does not exists in dictionary javascript
var person={"name":"Billy","age":20}
person.hasOwnProperty("name");
person.hasOwnProperty("gender");