jumble.js

'use strict';

chrome.browserAction.onClicked.addListener(function($) {
    Promise.all([getWindows(), getTabs()]).then(jumble);
});

function getWindows() {
    return new Promise(function(resolve, reject) {
        chrome.windows.getAll(resolve);
    });
}

function getTabs() {
    return new Promise(function(resolve, reject) {
        chrome.tabs.query({}, resolve);
    });
}

function jumble([windows, tabs]) {
    let windowTabCount = initializeWindowTabCount(windows);
    let tabGroup = groupBy(domain, tabs);

    let windowsToTabs = {};
    let domains = getOrderedDomains(tabGroup);
    domains.forEach(domain => {
        let w = leastCount(windowTabCount);
        w['tabcount'] += tabGroup[domain].length;
        chrome.tabs.move([...tabGroup[domain].map(t => t.id)], toWindow(w));
    });
}

function initializeWindowTabCount(windows) {
    return windows.reduce((a, w) => {
        a.push({ 'tabcount': 0, 'id': w.id });
        return a;
    }, []);
}

function groupBy(f, arr) {
    return arr.reduce((a, t) => {
        let key = f(t);
        (a[key] = a[key] || []).push(t);
        return a;
    }, {});
}

function domain(t) {
    return t.url.split('/')[2];
}

function getOrderedDomains(tabGroup) {
    return Object.keys(tabGroup).sort();
}

function leastCount(windowTabCount) {
    return windowTabCount.reduce((acc, w) => acc['tabcount'] < w['tabcount'] ? acc : w);
}

function toWindow(w) {
    return { "windowId": parseInt(w['id'], 10), index: -1 };
}