[enhacement] Use Flexible ascii progress bar.

[LeMoussel]

For a better understanding of the progress of the proxies checks, here is an example of code using an flexible ascii progress bar: node-progress.

Rem: Pool is not accessible via require('free-proxy-checker')

// https://github.com/antoinevastel/free_proxy_checker
const { ProxyChecker, downloadAllProxies, } = require('free-proxy-checker');
// https://github.com/visionmedia/node-progress
const ProgressBar = require('progress');

const { Pool } = require('./pool.js');

class ProgressProxyChecker extends ProxyChecker {
    async checkProxies() {
        this.lastCheck = Date.now();
        const pool = new Pool(this.options.concurrency);
        const pbar = new ProgressBar('Checking proxies [:bar] :percent :etas', {
            complete: '=',
            incomplete: ' ',
            width: 20,
            total: this.proxies.length
        });

        this.proxies.forEach((proxy) => {
            pool.addTask(async() => {
                try {
                    await proxy._testConnection(this.options.timeout);
                } catch (_) { }
                finally {
                    if (this.options.verbose) {
                        pbar.tick();
                    }
                }
            })
        })

        await pool.run();
    }
}

(async () => {
    // Clear console
    process.stdout.write('\033c');

    // Download all proxies from all proxy providers at once
    const allProxies = await downloadAllProxies();
    console.log(`There are ${allProxies.length} proxies to test`);

    // Check the availability of the proxies we downloaded
    const proxyChecker = new ProgressProxyChecker(allProxies, {
        concurrency: 50,
        timeout: 7500,
        verbose: true
    })

    await proxyChecker.checkProxies();
    const proxiesUp = proxyChecker.getProxiesUp();
    console.log(`There are ${proxiesUp.length} proxies UP:`);
})();

Result:

[antoinevastel]

Hi, thanks for your idea. Since node-progress is a single file + seems really stable I think it's reasonable to add it as a dependency without going through package.json.
I keep the issue open. I will probably do a PR in the next days/weeks :)

[antoinevastel]

I close the issue, I added the feature in this PR (#5) + publish new version on NPM. Once again thanks for idea + the code example