socketio net::ERR_ABORTED 404 (Not Found)

I've recently been learning about socket.IO.
I've hosted a static directory "Public" using express, and i imported socketio into the index.html.

<script src="../node_modules/socket.io/client-dist/socket.io.js"></script>

The browser will report an error:

GET http://127.0.0.1:3000/node_modules/socket.io/client-dist/socket.io.js net::ERR_ABORTED 404 (Not Found)

But I modified it this way：

<script src="/socket.io/socket.io.js"></script>

It works well!

Here is the folder directory structure

But the Public directory doesn't have any other js files,

So, where does it come from ?