Getting key with the highest value from object

Question

I have a object like that one:

Object {a: 1, b: 2, undefined: 1} 

How can I quickly pull the largest value identifier (here: b

Answer 1

For example:

var obj = {a: 1, b: 2, undefined: 1};

Object.keys(obj).reduce(function(a, b){ return obj[a] > obj[b] ? a : b });

In ES6:

var obj = {a: 1, b: 2, undefined: 1};

Object.keys(obj).reduce((a, b) => obj[a] > obj[b] ? a : b);