Babel NodeJS ES6: SyntaxError: Unexpected token export

Question

I'm trying to use babel to run my NodeJS program, which includes ES6 syntax and exports from the Colyseus library. However, when I run the command:

babel-node server.js

The following error message appears:

export class MyRoom extends colyseus.Room {
^^^^^^

SyntaxError: Unexpected token export

Below is my package.json file:

{
  "name": "app",
  "version": "1.0.0",
  "description": "a description",
  "main": "server.js",
  "scripts": {
    "test": "babel-node server.js",
    "build": "babel-node server.js"
  },
  "author": "henryzhu",
  "license": "ISC",
  "dependencies": {
    "actionhero": "^19.1.2",
    "colyseus": "^0.9.33",
    "easytimer.js": "^2.3.0",
    "express": "^4.16.3",
    "socket.io": "^2.1.0",
    "socketio": "^1.0.0",
    "uniqid": "^5.0.3"
  },
  "devDependencies": {
    "babel-cli": "^6.26.0",
    "babel-preset-env": "^1.7.0",
    "babel-preset-es2015": "^6.24.1"
  }
}

Below is my server.js file:

var colyseus = require("colyseus");
var http = require("http");
var express = require("express");
var port = process.env.port || 3000;

var app = express();

app.use(express.static("public", { dotfiles: 'allow' }));

var gameServer = new colyseus.Server({
  server: http.createServer(app)
});

export class MyRoom extends colyseus.Room {
    // When room is initialized
    onInit (options) { }

}

gameServer.listen(port);

what does your babel config look like?

miyu
– miyu

2019-03-24 23:31:49 +00:00
Commented Mar 24, 2019 at 23:31 — miyu
– miyu, Commented Mar 24, 2019 at 23:31

ryanpcmcquen · Accepted Answer · 2019-03-25 00:16:46Z

3

Add a config file with the following (.babel.config.js):

module.exports = {
    presets: [
        '@babel/preset-env'
    ]
};

Then run:

babel-node --config-file .babel.config.js server.js

answered Mar 25, 2019 at 0:16

ryanpcmcquen

6,5134 gold badges26 silver badges38 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

cglacet Over a year ago

That doesn't seem to work with "@babel/cli": "^7.2.3", "@babel/core": "^7.4.0", "@babel/node": "^7.2.2", "@babel/preset-env": "^7.0.0". I always fail to understand why there are so many ways for doing one such simple thing as transpiling some code in JS.

ryanpcmcquen Over a year ago

@cglacet, that is a different major version of Babel, have you checked their docs on this? I'm guessing a CLI flag changed between versions.

cglacet Over a year ago

I think I found the problem. If you have your config in your root/ directory and call a script that is in say root/folderA and that script imports something from root/folderB then the js file from folderB doesn't seem to be transpiled correctly (ignored?). That look like a bug to me but maybe I don't understand the responsibility of the config file (I had thought of it as a "project configuration" but apparently that's not how it is supposed to be understood).

Luca Fagioli Over a year ago

@cglacet I'm glad you consider JS transpiling "a simple thing". At this point, the whole community is waiting for you to write your personal transpiler. I am really curious to see it at work.

jsdeveloper · Accepted Answer · 2019-03-24 23:34:08Z

1

babel-node is presumably expecting the node style module syntax:

module.exports = ...

instead of the es6 style:

export class ...

EDIT:

You might be able to fix it by specifying a .babelrc file like so:

{
    "presets": ["env"]
}

with package babel-preset-env installed

answered Mar 24, 2019 at 23:34

jsdeveloper

4,0751 gold badge18 silver badges15 bronze badges

Comments

Amit Kulkarni · Accepted Answer · 2021-07-29 01:48:22Z

0

Adding a config file (babel.config.js) below worked for me. Also, the order is important. presets should be before all the plugins.

module.exports = {
     presets: [['@babel/preset-env',{targets: {node: 
        'current',},loose:true,},],],
     plugins: [
        '@babel/plugin-syntax-dynamic-import',
        '@babel/plugin-syntax-import-meta',
        [
        '@babel/plugin-transform-runtime',
        {
           useESModules: true,
        },
     ],
    ],
  };

answered Jul 29, 2021 at 1:48

Amit Kulkarni

819 bronze badges

Collectives™ on Stack Overflow

Babel NodeJS ES6: SyntaxError: Unexpected token export

3 Answers 3

4 Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

4 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related