I'm currently working on an application built with Express. I have tried to implement robots.txt.

This is what I have right now:

app.use(
    '/robots.txt', 
    function (req, res) {
        res.type('text/plain');
        res.send("User-agent: *\nAllow: /\nDisallow: /search")
     );
 });

While I am able to see the results in the website, google search is giving me the warning:

Indexed, though blocked by robots.txt

Am I doing something wrong or is there a better way to implement the robots.txt file?