How can I use a variable as a key to a JavaScript object?

Question

My code is as follows:

var currency = "USD";
var value = 100;

function test(currency, value) {
    var myObject = {("" + currency): value};
    console.log(myObject);
}

test(currency, value);

I'm trying to get an object as follows:

{"USD": 100}

How do I fix my code to do this?

Answer 1

You could take a computed property name for the object.

function test(currency, value) {
    return { [currency]: value };
}

var currency = "USD",
    value = 100;

console.log(test(currency, value));

Answer 2

In javascript we can add object with:

• dot notation
• square brackets

But only second case allows to access/add properties dynamically like this-

var currency = "USD";
var value = 100;
var myObject = {};

function test(currency, value) {
  myObject[currency] = value;
  console.log(myObject);
}

test(currency, value);