use #std/esm to use ES6 in Express node.js project - node.js

Question

I'm working on a Node.js project. I'm trying to use ES6 feature (like "import", "export") with a new ESM library but I'm struggling how to use it in Express app.
Here is what I have done:
Run npm i --save #std/esm in the project directory.
In index.js add "require("#std/esm")" to first line
use ESS "import"
here is my index.js
require("#std/esm")
// const express = require( "express" );
import express from '../node_modules/express'
const router = express.Router();
/* GET home page. */
router.get( "/", ( req, res, next ) => {
res.render( "index", { "title": "Express" } );
} );
// export default router
module.exports = router;
Run the project but I get this error
/usr/local/bin/node /Volumes/Elements/Learning/Node/Project/NodeMongoTest1/routes/index.js
/Volumes/Elements/Learning/Node/Project/NodeMongoTest1/routes/index.js:3
import express from '../node_modules/express'
^^^^^^
SyntaxError: Unexpected token import
at new Script (vm.js:51:7)
at createScript (vm.js:136:10)
at Object.runInThisContext (vm.js:197:10)
at Module._compile (module.js:626:28)
at Object.Module._extensions..js (module.js:673:10)
at Module.load (module.js:575:32)
at tryModuleLoad (module.js:515:12)
at Function.Module._load (module.js:507:3)
at Function.Module.runMain (module.js:703:10)
at startup (bootstrap_node.js:193:16)
Process finished with exit code 1
Any know how to config ESM with Express Node.js?

Answer 1

There are three ways to enable ESM with #std/esm.
Enable ESM with a CJS bridge:
index.js
// Provide options as a parameter, environment variable, or rc file.
require = require("#std/esm")(module/*, options*/)
module.exports = require("./main.mjs").default
Enable ESM in the Node CLI with the -r option:
node -r #std/esm main.mjs
Enable ESM in the Node REPL:
node -r #std/esm
Try #2 first to check whether rest of code is correct in index file