Asynchronously manipulate URLS found in a text paragraph - PoC

main.js

const linkify = require('linkifyjs');


function sleep(delay = 500) {
    return new Promise(resolve => {
        setTimeout(resolve, delay);
    });
}


class Placeholder {}


async function replaceLinksEfficiently(str, callback) {
    const tokens = linkify.tokenize(str);
    let result = [];
    const promises = [];

    for (let i = 0; i < tokens.length; i++) {
        let token = tokens[i];

        if (!token.isLink) {
            result.push(token.toString());
            continue;
        }

        let formattedHref = token.toHref('http');

        result.push(new Placeholder());
        promises.push(new Promise((resolve, reject) => {
            callback(formattedHref).then(resolve);
        }));
    }

    const newValues = await Promise.all(promises);
    result = result.map(part => part instanceof Placeholder ? newValues.shift() : part);

    return result.join('');
}


async function replaceLinks(str, callback) {
    const tokens = linkify.tokenize(str);
    let result = [];

    for (let i = 0; i < tokens.length; i++) {
        let token = tokens[i];

        if (!token.isLink) {
            result.push(token.toString());
            continue;
        }

        let formattedHref = token.toHref('http');

        // TODO consider something with Promise.all for simultaneously replace links
        let link = await callback(formattedHref);
        result.push(link);
    }

    return result.join('');
}


function main() {
    const str = 'hello http://google.com/ world! (github.com). dev.to. go to bit.ly/p?1=2&3=4#5 now. "google.com" 3.99$ ';

    async function convert(match) {
        console.log(`converting... ${match}`);
        await sleep();
        return `<${match}>`;
    }

    replaceLinksEfficiently(str, convert).then(result => {
        console.log('Converted content:', result);
    });
}


if (require.main === module) {
    main();
}

Output of the above:

converting... http://google.com/
converting... http://github.com
converting... http://dev.to
converting... http://bit.ly/p?1=2&3=4#5
converting... http://google.com
Converted content: hello <http://google.com/> world! (<http://github.com>). <http://dev.to>. go to <http://bit.ly/p?1=2&3=4#5> now. "<http://google.com>" 3.99$

---

replaceLinks iterates all found URLs one by one (uses await).

replaceLinksEfficiently uses Promise.all() to process all found URLs at once.