[Fixed] Node.js express.Router ERR_MODULE_NOT_FOUND when import the new routes

Issue

I am experiencing a weird error. I was just creating a new folder to separate my routes.

Inside I created the routes using the express.Router API and I exported the router itself.

Here is how the code looks like inside post-routes.ts:

import express from 'express';

const router = express.Router();

router.get( '/', ( req, res ) =>
{
    res.send( 'This is working' );
} );

export default router;

Ok. All I have to do now is to import it inside my index.ts and create a root route for my post-routes.ts file.

Please tell me if you see something wrong in my approach.

index.ts file:

import express from 'express';
import cors from 'cors';
import postRouter from './routes/post-routes';

const PORT = process.env.PORT || 5000;

app.use( '/posts', postRouter );


app.use( express.json( { limit: '30mb' } ) );
app.use( express.urlencoded( { limit: '30mb', extended: true } ) );
app.use( cors() );

app.listen( PORT, () => console.log( `listening at ${ PORT }` ) );

Good. Now to offer as much information as I possibly can, I will insert the following:

1. File structure inside my project:

2. package.json file configuration:

As you can see, I am using the "type": "module" to be able to use import inside my node application. As for the typescript, I am getting no compiling errors, so index.ts sees the post-routes.ts file so I would expect that index.js would see post-routes.js file as well. But the server throws the error below. How can this be?

Error [ERR_MODULE_NOT_FOUND]: Cannot find module 'E:\Github\hospytal-fasion\server\dist\routes\post-routes' imported from E:\Github\hospytal-fasion\server\dist\index.js

Solution

Apart from making sure that target and module are set to esnext in your tsconfig.json, make sure to include file extensions in your imports. i.e. try changing the following line:

import postRouter from './routes/post-routes';

to

import postRouter from './routes/post-routes.ts';