Javascript object unique ID with variable

Question

I'm trying to use a unique ID to store a JSON object in an array so that I can pull out that specific object at a later date in my code, however my expected output isn't happening:

var applications = []

var key = 50

var obj = {
  key: {
    "name": "John"
  }
}

// expected output:
//
// [{
//   '50': {
//     "name": "John"
//   }
// }]
// 

applications.push(obj)

You've hardcoded the property name `key`, see [computed property names](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Object_initializer#Examples). — Teemu, Jun 04 '20 at 09:45

score 3 · Answer 1 · answered Jun 04 '20 at 09:47

3

In order to use a dynamic key, we just need to wrap that key in square brackets [] like:

var applications = []
var key = 50
var obj = {
  [key]: {
    "name": "John"
  }
}
applications.push(obj)

console.log(applications)

answered Jun 04 '20 at 09:47

palaѕн

72,112
17
116
136

1

Did not know about the square bracket method to use a string as the name of the key, thanks for that! – dehart Jun 04 '20 at 09:49
Note: it is not working on ES5 – Hamza Ezzaydia Jun 04 '20 at 09:58

score 0 · Answer 2 · answered Jun 04 '20 at 09:54

0

Adding [] is available from ES6 and Babel and not ES5

For compatibility you need to make the object first, then use [] to set it.

var key = 50;
var obj = {};
obj[key] = someValueArray;
applications.push(obj);

answered Jun 04 '20 at 09:54

Hamza Ezzaydia

267
2
13

Javascript object unique ID with variable

2 Answers2