I have following object structure, and

[
  { id: 183, firstName: 'first0', lastName: 'last0', std: 0 },
  { id: 184, firstName: 'first1', lastName: 'last1', std: 1 },
  { id: 185, firstName: 'first2', lastName: 'last2', std: 2 }
]

I want to iterate through the object and get [183,184,185]. Here is what I have tried

alreadyCachedData = [
  { id: 183, firstName: 'first0', lastName: 'last0', std: 0 },
  { id: 184, firstName: 'first1', lastName: 'last1', std: 1 },
  { id: 185, firstName: 'first2', lastName: 'last2', std: 2 }
]
for (var key in alreadyCachedData[0]) {
  if (alreadyCachedData[0].hasOwnProperty(key)  == "id") {
    var val = alreadyCachedData[0][key];
    console.log(val);
  }
} 

But I don't get required result, any help?