JSFiddle - React, Tailwind, and code Playground

HTML

<div id="output"></div>

JavaScript

var source = [
    ['bourbon', 2],
    ['bourbon', 1],
    ['scotch', 2]
];
var hash = {};
var consolidated = [];

source.forEach(function (item) {
    hash[item[0]] = (hash[item[0]] || 0) + item[1];
});

Object.keys(hash).forEach(function (key) {
    consolidated.push([key, hash[key]]);
});

document.getElementById('output').innerHTML = JSON.stringify(consolidated);