Check available 2-letter names on "clusters" in NodeJS, using Puppeteer to parse JavaScript-generated content

react-crawler.js

(async () => {
    const puppeteer = require('puppeteer'),
        fs = require('fs').promises,

        // Generate 2-letter combinations
        generateCombinations = x => {
            const combinations = [],
            // Small latin letters and digits
                characters = [...Array(26).keys()].map(i => String.fromCharCode(i + 97))
                            .concat([...Array(10).keys()].map(i => i.toString()));

            // Generate combinations
            characters.forEach(char1 => {
                characters.forEach(char2 => {
                    combinations.push(char1 + char2);
                });
            });

            return combinations;
        },

        // Output all combinations
        allCombinations = generateCombinations(),
        startFrom = "wt"; // start checking from this combination. Can be empty or false to check all possible combinations.


    // GO!
    let browser, html,
        started;

    for (let i in allCombinations) {
        let combination = allCombinations[i];
        console.log(combination);

        if (!started && (!startFrom || combination === startFrom)) {
            // initiate the browser
            browser = await puppeteer.launch(); // or { headless: false }?
            started = 1;
        }

        if (started) {
            // create a new in headless chrome
            const page = await browser.newPage();
        	// go to target website
        	await page.goto('https://clusters.xyz/bid/' + combination, {
        		// wait for content to load
        		waitUntil: 'networkidle0' //'domcontentloaded',
        	});

        	// get full page html
        	html = await page.content();

            if (html.indexOf("Name is not available") === -1) {
            	await fs.writeFile('available_names.txt', combination + "\n", { flag: "a+"});
                console.log('FOUND! ' + combination);
            }

            /* // if you need a screenshot
            await page.screenshot({
                path: 'screenshot_full.jpg',
                fullPage: true
            }); */

        	// Store html content in the reactstorefront file
        	// await fs.writeFile('last_checked_page.html', html);

        	//close headless chrome
        	await page.close();
        }
    }
    
    process.exit();
})();