How to check if a key exists in an object in javascript [duplicate]

Question

I have the following object literal:

{ 
  'key1': 
  { 
    id: 'rr323',
    d: undefined,
    x: 560,
    y: 150 
  },
  'key2': 
  { 
    id: 'rr231',
    d: undefined,
    x: 860,
    y: 90 
  } 
}

I want to implement an if statement such as below:

if(key DOES NOT exist in object){  
//perform certain function 
}

I tried the following:

var key = key1;
if(!(key in global_move_obj)){
 // function
}

But that always returns true value when it should return false.

Answer 1

You can do it like:

var key = 'key1';
if (!('key1' in obj)) {
    ....
} 
// or
if (!(key in obj)) {

}