SyntaxError: Unexpected token import - Express

Question

I have this in my index.js

import express from 'express'
import data from './data/data'


const app = express();
const PORT = 3000; 

app.listen(PORT, () =>
    console.log(`Your server is running on ${PORT}`)
);

This is my package.json

{
    "name": "express-app",
    "version": "1.0.0",
    "description": "backend provisioning",
    "main": "app.js",
    "scripts": {
        "start": "nodemon ./index.js --exec babel-node -e js"
    },
    "author": "B",
    "license": "ISC",
    "devDependencies": {
        "babel-cli": "^6.26.0",
        "babel-preset-env": "^1.6.1",
        "babel-preset-stage-0": "^6.24.1"
    },
    "dependencies": {
        "express": "^4.16.3"
    }
}

When I run nodemon , I got

[nodemon] 1.17.3
[nodemon] to restart at any time, enter `rs`
[nodemon] watching: *.*
[nodemon] starting `node index.js`
/Users/b/Desktop/express-app/index.js:1
(function (exports, require, module, __filename, __dirname) { import express from 'express'
                                                            ^^^^^^

SyntaxError: Unexpected token import
    at createScript (vm.js:80:10)
    at Object.runInThisContext (vm.js:139:10)
    at Module._compile (module.js:607:28)
    at Object.Module._extensions..js (module.js:654:10)
    at Module.load (module.js:556:32)
    at tryModuleLoad (module.js:499:12)
    at Function.Module._load (module.js:491:3)
    at Function.Module.runMain (module.js:684:10)
    at startup (bootstrap_node.js:187:16)
    at bootstrap_node.js:608:3
[nodemon] app crashed - waiting for file changes before starting...

Did I forget to do anything to be able to use the import command?

I did this :

npm install --save-dev babel-cli babel-preset-env babel-preset-stage-0
npm install express
nodemon

same result

I also try this

rm -rf node_modules/
npm install
nodemon

same result

---

.babelrc

{
    "presets":[
        "env",
        "stage-0"
    ]
}

Solution 1

NodeJS supports import natively only experimentally, and only if your script has the .mjs extension.

That's why the start in your package.json is referring to babel-node, which transpiles ES6 code into classic JS on-the-fly before running it. But I doubt even that command will work, because you're not passing any presets to babel to run the script. Try this command:

nodemon --exec babel-node --presets env index.js

[OR]

Rename your file to have .mjs extension, then run this:

nodemon --experimental-modules index.mjs

Solution 2

This happens if you have lower version of node. please upgrade it to at least v10.0

Comments

[code-8]

I tried your first option, I got the same result, when running nodemon.

[code-8]

My node version is v8.9.4

[Vasan]

@ihue I just tried your exact script on 8.9.4 in my box, and it works for me. Are you sure you executed my command exactly as provided? And are you getting exactly the same error as in your question?

[code-8]

I suppose to do npm start not nodemon

[Vasan]

@ihue Ok, so you changed your package.json to use my command then?

[Vasan]

@ihue I corrected my answer, it looks like experimental support is available in version 8 as well. So you might want to try my second option if the first is still not working (I checked again and both options do work on 8.9.4)