Given array of integers, find its mode. (the number which appears most often in it)

findModeInArrayOfIntegers.js

// Given array of integers, find its mode. (the number which appears most often in it)

function arrayMode(sequence) {
    var arr = {};
    for (var i=0; i < sequence.length; i++) {
        var num = sequence[i];
        if (arr[num] === undefined){
            arr[num] = 0;
        } 
        arr[num] += 1;
    }

    var greatest = 0; 
    var mode = 0;
    Object.keys(arr).forEach(function(key) {
        if (arr[key] > greatest) {
            greatest = arr[key];
            mode = key;
        }
    });
    return parseInt(mode);
}