JSFiddle - React, Tailwind, and code Playground

JavaScript

var a = [
        [1, 2],
        [3, 4],
        [5, 6],
        [7, 8]
    ],
    sumColumnJS = function sumColumnJS(array, col) {
        var sum = 0;
        array.forEach(function (value, index, array) {
            sum += value[col];
        });
        return sum;
    },
    sumColumn_ = function sumColumn_(array, col) {
        var sum = 0;
        _.each(a, function (item) {
            sum += item[col];
        });
        return sum;
    };
console.log(sumColumnJS(a, 0));
console.log(sumColumnJS(a, 1));
console.log(sumColumn_(a, 0));
console.log(sumColumn_(a, 1));