nightmare + vo

scraper.ts

const Nightmare = require ("nightmare");
const vo = require("vo");

function scrape (url: string, dataScraper: Function, urlScraper: Function, 
                 injectJQuery: boolean = true, validate: Function = null)
{
    var item : any = null, urls: any = null;
    // do not show window, do not load images (reduce time to ready())
    var nightmare = Nightmare({show: false, pollInterval: 800, webPreferences: {images: false}});

    function * workflow () {
        // load url in Electron instance
        yield nightmare.goto(url);
        if (injectJQuery)
            // injects jQuery library into loaded page (inserts script tag inside DOM)
            yield nightmare.inject("js", "client\\jquery.js");
        if (dataScraper != null)
            // evaluate javascript function into loaded page (client side)
            item = yield nightmare.evaluate(dataScraper);
        if (urlScraper != null)
            // executes url workflow and returns result
            urls = yield vo(urlScraper(nightmare));
        // destroys Electron instance
        yield nightmare.end();
    }

    return vo(workflow)
        .catch((error) => {console.log(error);})
        .then (() => {
            if (item != null && validate != null)
                validate(item);
        });
}

function * urlScraper (nightmare) {
    var urls = [];
    var nextPage: boolean = true;

    while (nextPage) {
        // evaluates javascript function into loaded page (client side)
        // tip: do not return jQuery objects to the node.js side
        var urlsInPage = yield nightmare
            .evaluate (function () { return jQuery.map($(".listing a"), (d) => d.href); });
        urls = urls.concat(urlsInPage);
        // evaluates javascript function into loaded page (client side)
        nextPage = yield nightmare.evaluate(function () {return $(".pagination a.next").length > 0;});
        if (nextPage)
            // triggers click event into loaded page to load next page
            yield nightmare.click(".pagination a.next");
    }
    return urls;
}

scrape("http://anywebyouwanttoscrape.com", Function("return $(.email).text();"), urlScraper, true, null);