获取包含NULL值的JavaScript / angularJS对象键

Question

i have bind object 'p' with input fields using angularJS like this

<input ng-model="p.p1" type="text" />
<input ng-model="p.p2" type="text" />
<input ng-model="p.p3" type="text" />

it seems like my object is like this when these inputs are empty:

var p =
  {
    "p1": null,
    "p2": null,
    "p3": null
  };

I have tried

 Object.keys(p); // return [] (empty array)

Can any one tell me how I can get list of all keys contains in JavaScript object, including keys which contain null value as well ?

Answer 1

Iterate through for loop and get those keys which have null.

for(var key in p) {
    if(p[key] == null) {
       // do your stuff here!
    }
}

Answer 2

why not use p.p1 ? or else you can always use p['p1'] ? if you don't define the key you want to access its free for the garbage collector to clean up.

You need to place a hook in your code that accesses that key directly, otherwise it will get cleaned up.

Answer 3

Please try the below one. Object.keys in not supported in major browsers, So have a polyfill for that.

var p =
  {
    "p1": null,
    "p2": null,
    "p3": null
  },key;

function getObjectKeys(p){

  if(Object.keys){
    key = Object.keys(p);

    return key;
  }else{
    key = [];
    for(var k in p){ 
      key.push(k);
    }
    return key;
  }
}

getObjectKeys(p);

Live output

Answer 4

Thank you all for your response, Actually the problem is not in JS code rather problem is with angularJS binding. its not put any key+value in object when input field is empty. so that's why i got object like this

 var p = {}; // $scope.p is looks same as this

so i did not got any key from

Object.keys(p); // is also working fine.

other solutions posted by other guys are also work fine.