How can I configure Express to use EJS with .html files in an ES module project?

Since you're using ES modules (i.e. "type": "module" in package.json), the CommonJS function require isn't directly available. You have two options:

1. Use the ES module equivalent:
   Import the module normally and use its export. For example, if EJS exposes renderFile, you can import it:

   JAVASCRIPTCopied
   import express from "express";
   import bodyParser from "body-parser";
   import ejs from "ejs";
   
   const app = express();
   const port = 3001;
   
   app.engine('html', ejs.renderFile);
   // app.set('view engine', 'html')
   app.use(express.static("public"));
   
   const currentYear = new Date().getFullYear();
   
   app.use(bodyParser.urlencoded({ extended: true }));
   
   app.get("/", (req, res) => {
     const data = {
       title: "welcome page",
       year: currentYear,
     };
     res.render("index.html", data);
   });
   
   app.listen(port, () => {
     console.log(`Listening on port ${port}`);
   });

2. Use createRequire to access require:
   If you absolutely need to use require, Node.js provides a helper function called createRequire from the "module" package. You can use it to define require within your ES module scope:

   JAVASCRIPTCopied
   import express from "express";
   import bodyParser from "body-parser";
   import { createRequire } from "module";
   const require = createRequire(import.meta.url);
   
   const app = express();
   const port = 3001;
   
   app.engine('html', require('ejs').renderFile);
   // app.set('view engine', 'html')
   app.use(express.static("public"));
   
   const currentYear = new Date().getFullYear();
   
   app.use(bodyParser.urlencoded({ extended: true }));
   
   app.get("/", (req, res) => {
     const data = {
       title: "welcome page",
       year: currentYear,
     };
     res.render("index.html", data);
   });
   
   app.listen(port, () => {
     console.log(`Listening on port ${port}`);
   });

Both methods work while preserving your ES module structure. Which approach you choose depends on your preference and potential library needs.