const handler = new DomHandler([ <func> callback(err, dom), ] [ <obj> options ]);
// const parser = new Parser(handler[, options]);

const { Parser } = require("htmlparser2");
const { DomHandler } = require("domhandler");
const rawHtml =
    "Xyz <script language= javascript>var foo = '<<bar>>';</script><!--<!-- Waah! -- -->";
const handler = new DomHandler((error, dom) => {
    if (error) {
        // Handle error
    } else {
        // Parsing completed, do something
        console.log(dom);
    }
});
const parser = new Parser(handler);
parser.write(rawHtml);
parser.end();