Get the Key of the highest Value in JavaScript object [closed]

I don't know about elegant, but you can omit the initial _(), use + to convert to number instead of parseInt and just pull out the iterator.

var iterator = function(p){return p[1];}
var maxKey = +_.chain(b).pairs().max(iterator).value()[0];
// Removed the | 0 since the keys are integers to begin with

Here's an alternate way to do it using ES5 Array.prototype.reduce and Object.keys. You can also use underscore's _.reduce and _.keys for compatibility. Note that this runs through the entire array, so any duplicates found will use the latest value.

var max = Object.keys(b).reduce(function(max,key){
  return (max === undefined || b[key] > b[max]) ? +key : max;
});

Making it more clear what we're doing, in case you aren't familiar of reduce, is to use Array.prototype.forEach (or _.each):

var max;
Object.keys(b).forEach(function(key){
  max = (b[key] > b[max]) ? +key : max;
});

The way I would do this with the current iteration of underscore (1.6) would be through reduce. Note use _.reduceRight if you want to favour items to the left

_.reduce(b, function(max, current, key) {
    return max && max.value > current ? max : {
        value: current,
        key: key
    };
}).key

However, in lodash you can use findKey which would be more intuitive. _.findKey will be available in underscore 2.0 if they accept my pull request #1587

var maxValue = _.max(b);
_.findKey(b, function(x) {
    return x === maxValue;
});