How do I interpolate a variable as a key in a JavaScript object?

Question

How can I use the value of the variable a as a key to lookup a property? I want to be able to say: b[\"whatever\"] and have this return 20:

Answer 1

Great question. I had a time trying to figure this out with underscore but the answer couldn't be more simple:

var a = "whatever";
var b = {a : 20};

var array = [a, b]
var answer = _.object([[array]])// {whatever: {a:20}}//NOTICE THE DOUBLE SET OF BRACKETS AROUND [[array]]

I hope this helps!