const http = require('http');
const fs = require('fs');

http.createServer(function (request, response) {
    fs.readFile('index.html', 'utf8', function (error,data) 
    {
        let message = 'Изучаем Node.js';
        let header = 'Главная страница';
        dataNew = data
            .replace('{header}', header)
            .replace('{message}', message);
        response.end(dataNew);
    });
}).listen(3000);