JavaScript set object key by variable [duplicate]

Question

This question already has an answer here:

• How to use a variable for a key in a JavaScript object literal? 9 answers
• How do I create a dynamic key to be added to a JavaScript object variable [duplicate] 2 answers

I am building some objects in JavaScript and pushing those objects into an array, I am storing the key I want to use in a variable then creating my objects like so:

var key = "happyCount";
myArray.push( { key : someValueArray } );

but when I try to examine my array of objects for every object the key is "key" instead of the value of the variable key. Is there any way to set the value of the key from a variable?

Fiddle for better explanation: http://jsfiddle.net/Fr6eY/3/

Answer 1

You need to make the object first, then use [] to set it.

var key = "happyCount";
var obj = {};
obj[key] = someValueArray;
myArray.push(obj);

UPDATE 2018:

If you're able to use ES6 and Babel, you can use this new feature:

{
    [yourKeyVariable]: someValueArray,
}  

Answer 2

Try something like this (check ES6 example at the end of answer)

var yourObject = {};

yourObject[yourKey] = "yourValue";

console.log(yourObject );

example:

var person = {};
var key = "name";

person[key] /* this is same as person.name */ = "John";

console.log(person); // should print  Object { name="John"}

    var person = {};
    var key = "name";
    
    person[key] /* this is same as person.name */ = "John";
    
    console.log(person); // should print  Object { name="John"}

In ES6, you can do like this.

var key = "name";
var person = {[key]:"John"};
console.log(person); // should print  Object { name="John"}

    var key = "name";
    var person = {[key]:"John"};
    console.log(person); // should print  Object { name="John"}