Find the index of the longest array in an array of arrays

Question

If you have an array containing an indefinite amount of arrays

ex:

var masterArray = [ [1,2,3,4,5],
                    [1,2], 
                    [1,1,         


        

Answer 1

Using lodash:

_.max(_.map(masterArray, function(v, k) { return { id: k, size: v.length }; }),'size').id;

This creates a new array with objects having 'id' and 'size', then finds the maximum size in that array, and returns its 'id'.

jsfiddle: https://jsfiddle.net/mckinleymedia/8xo5ywbc/