return the largest value's key in an object javascript code example

Example 1: find in highest value key from an object javascript

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

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

Example 2: which object key has highest value javascript

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

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