src code

class method Object.isUndefined 

Object.isUndefined(object) → Boolean
  • object (Object) – The object to test.

Returns true if object is of type undefined; false otherwise.

Examples
Object.isUndefined();
//-> true
 Object.isUndefined(undefined);
//-> true
 Object.isUndefined(null);
//-> false
 Object.isUndefined(0);
//-> false
 Object.isUndefined("");
//-> false