Setting an Array Element as an Object Property [duplicate]

Question

I am trying to set an array element as an object Property

Simplified example:

var array = ['a', 'b', 'c'];
var obj = { array[1]: 'good' }

Above causes an error.

Update: In fact, I am passing the object as a part of another array ie a simplified example would be:

aObj[value] = ['one', {array[1]: 'good'}, 'two', 'three', 'four'];

Setting the obj[array[1]] = 'good'; style would mean using

aObj[value][1][array[1]] = 'good';

Answer 1

{ array[1]: 'good' } throws an error because, when you use the Object literal notation in JavaScript, it treats the string before : as the identifier and a valid identifier name cannot have [ or ] in it.

So, use the [] notation, which allows any string to be used as the property name, like this

var array = ['a', 'b', 'c'];
var obj = {};
obj[array[1]] = 'good';

Answer 2

Maybe it's time to start giving ES6 answers too. In ECMAScript6 you can use expressions as object keys:

var array = ['a', 'b', 'c'];
var obj = {
    [array[1]]: 'good'
}

In fact, this syntax is already supported in Firefox.

Currently the only way to use variable is to use bracket notation as described in other answer.