How to fix middleware function error app.use

Question

I already installed Express, Nodeman, Express-Edge. I using Windows 10. Someone who had a similar problem with me was told that he needed to install the library he had specified. Like I said I already installed it.

in index.js codes;

 const path = require('path');
const expressEdge = require('express-edge');
const express = require('express');

const app = new express();

app.use(express.static('public'));
app.use(expressEdge);
app.set('views', __dirname + '/views');

app.get('/', (req, res) => {
    res.render('index');
});

app.get('/about', (req, res) => {
    res.sendFile(path.resolve(__dirname, 'pages/about.html'));
});

app.get('/contact', (req, res) => {
    res.sendFile(path.resolve(__dirname, 'pages/contact.html'));
});

app.get('/post', (req, res) => {
    res.sendFile(path.resolve(__dirname, 'pages/post.html'));
});

app.listen(4000, () => {
    console.log('App listening on port 4000')
});

command shell saying:

C:\Users\Maximus\WebstormProjects\untitled4\nodejs-blog-tutorial\node_modules\express\lib\application.js:210
    throw new TypeError('app.use() requires a middleware function')
    ^

TypeError: app.use() requires a middleware function
    at Function.use (C:\Users\Maximus\WebstormProjects\untitled4\nodejs-blog-tutorial\node_modules\express\lib\application.js:210:11)
    at Object.<anonymous> (C:\Users\Maximus\WebstormProjects\untitled4\nodejs-blog-tutorial\index.js:8:5)
    at Module._compile (internal/modules/cjs/loader.js:1137:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1157:10)
    at Module.load (internal/modules/cjs/loader.js:985:32)
    at Function.Module._load (internal/modules/cjs/loader.js:878:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:71:12)
    at internal/main/run_main_module.js:17:47
[nodemon] app crashed - waiting for file changes before starting...

package.json

{
  "name": "nodejs-blog-tutorial",
  "version": "1.0.0",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "keywords": [
    "blog"
  ],
  "description": "",
  "dependencies": {
    "express": "^4.17.1",
    "express-edge": "^2.0.2",
    "nodemon": "^2.0.4",
    "startbootstrap-clean-blog": "^5.0.9"
  }
}

hi interesting, not sure, maybe this would be of interest https://stackoverflow.com/questions/32883626/typeerror-app-use-requires-middleware-functions — IronMan, Sep 15 '20 at 23:33
See the official usage: https://www.npmjs.com/package/express-edge. — Take-Some-Bytes, Sep 15 '20 at 23:35

score 1 · Accepted Answer · answered Sep 15 '20 at 23:35

It appears you aren't using the right export from the express-edge library. Per the documentation, it should be this:

const express = require('express');
const expressEdge = require('express-edge');

const app = new express();
app.use(expressEdge.engine);

Or, you could do it like this:

const express = require('express');
const { config, engine } = require('express-edge');

const app = new express();
app.use(engine);

The idea here is that expressEdge exports an object that has two properties config and engine and you have to access those properties in order to use the library properly.

I changed the app.use(expressEdge); to app.use(expressEdge.engine); and worked. Thank you! @jfrind00 — Berat K., Sep 15 '20 at 23:39

How to fix middleware function error app.use

1 Answers1