"unexpected token import" in Nodejs5 and babel?

Question

In js file, i used import to instead of require

import co from 'co';

And tried to run it directly by nodejs since it said import is 'shipping features' and support without any runtime flag (https://nodejs.org/en/docs/es6/), but i got an error

import co from 'co';
^^^^^^

SyntaxError: Unexpected token import

Then i tried to use babel

npm install -g babel-core
npm install -g babel-cli
npm install babel-core //install to babel locally, is it necessary?

and run by

babel-node js.js

still got same error, unexpected token import?

How could I get rid of it?

Answer 1

From the babel 6 Release notes:

Since Babel is focusing on being a platform for JavaScript tooling and not an ES2015 transpiler, we’ve decided to make all of the plugins opt-in. This means when you install Babel it will no longer transpile your ES2015 code by default.

In my setup I installed the es2015 preset

npm install --save-dev babel-preset-es2015

or with yarn

yarn add babel-preset-es2015 --dev

and enabled the preset in my .babelrc

{
  "presets": ["es2015"]
}

Answer 2

Until modules are implemented you can use the Babel "transpiler" to run your code:

npm install --save babel-cli babel-preset-node6

and then

./node_modules/babel-cli/bin/babel-node.js --presets node6 ./your_script.js

If you dont want to type --presets node6 you can save it .babelrc file by:

{
  "presets": [
    "node6"
  ]
}

See https://www.npmjs.com/package/babel-preset-node6 and https://babeljs.io/docs/usage/cli/

Answer 3

1. Install packages: babel-core, babel-polyfill, babel-preset-es2015
2. Create .babelrc with contents: { "presets": ["es2015"] }
3. Do not put import statement in your main entry file, use another file eg: app.js and your main entry file should required babel-core/register and babel-polyfill to make babel works separately at the first place before anything else. Then you can require app.js where import statement.

Example:

index.js

require('babel-core/register');
require('babel-polyfill');
require('./app');

app.js

import co from 'co';

It should works with node index.js.

Answer 4

babel-preset-es2015 is now deprecated and you'll get a warning if you try to use Laurence's solution.

To get this working with Babel 6.24.1+, use babel-preset-env instead:

npm install babel-preset-env --save-dev

Then add env to your presets in your .babelrc:

{
  "presets": ["env"]
}

See the Babel docs for more info.

Answer 5

if you use the preset for react-native it accepts the import

npm i babel-preset-react-native --save-dev

and put it inside your .babelrc file

{
  "presets": ["react-native"]
}

in your project root directory

https://www.npmjs.com/package/babel-preset-react-native

Answer 6

It may be that you're running uncompiled files. Let's start clean!

In your work directory create:

• Two folders. One for precompiled es2015 code. The other for babel's output. We'll name them "src" and "lib" respectively.

• A package.json file with the following object:

  { 
    "scripts": {
        "transpile-es2015": "babel src -d lib"
    },
    "devDependencies": {
        "babel-cli": "^6.18.0",
        "babel-preset-latest": "^6.16.0"
    }
  }
  

• A file named ".babelrc" with the following instructions: {"presets": ["latest"]}

• Lastly, write test code in your src/index.js file. In your case: import co from 'co'.

Through your console:

• Install your packages: npm install
• Transpile your source directory to your output directory with the -d (aka --out-dir) flag as, already, specified in our package.json: npm run transpile-es2015
• Run your code from the output directory! node lib/index.js

Answer 7

Current method is to use:

npm install --save-dev babel-cli babel-preset-env

And then in in .babelrc

{
    "presets": ["env"]
}

this install Babel support for latest version of js (es2015 and beyond) Check out babeljs

Do not forget to add babel-node to your scripts inside package.json use when running your js file as follows.

"scripts": {
   "test": "mocha",
    //Add this line to your scripts
   "populate": "node_modules/babel-cli/bin/babel-node.js" 
},

Now you can npm populate yourfile.js inside terminal.

If you are running windows and running error internal or external command not recognized, use node infront of the script as follow

node node_modules/babel-cli/bin/babel-node.js

Then npm run populate

Answer 8

You have to use babel-preset-env and nodemon for hot-reload.

Then create .babelrc file with below content:

{
  "presets": ["env"]
}

Finally, create script in package.json:

"scripts": {
    "babel-node": "babel-node --presets=env",
    "start": "nodemon --exec npm run babel-node -- ./index.js",
    "build": "babel src -d dist"
  }

Or just use this boilerplate:

Boilerplate: node-es6

Answer 9

• install --> "npm i --save-dev babel-cli babel-preset-es2015 babel-preset-stage-0"

next in package.json file add in scripts "start": "babel-node server.js"

    {
  "name": "node",
  "version": "1.0.0",
  "description": "",
  "main": "server.js",
  "dependencies": {
    "body-parser": "^1.18.2",
    "express": "^4.16.2",
    "lodash": "^4.17.4",
    "mongoose": "^5.0.1"
  },
  "devDependencies": {
    "babel-cli": "^6.26.0",
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-stage-0": "^6.24.1"
  },
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "babel-node server.js"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

and create file for babel , in root ".babelrc"

    {
    "presets":[
        "es2015",
        "stage-0"
    ]
}

and run npm start in terminal

Answer 10

Involve following steps to resolve the issue:

1) Install the CLI and env preset

$ npm install --save-dev babel-cli babel-preset-env

2) Create a .babelrc file

{
  "presets": ["env"]
}

3) configure npm start in package.json

"scripts": {
    "start": "babel-node ./server/app.js",
    "test": "echo \"Error: no test specified\" && exit 1"
  }

4) then start app

$ npm start

Answer 11

I have done the following to overcome the problem (ex.js script)

problem

$ cat ex.js
import { Stack } from 'es-collections';
console.log("Successfully Imported");

$ node ex.js
/Users/nsaboo/ex.js:1
(function (exports, require, module, __filename, __dirname) { import { Stack } from 'es-collections';
                                                              ^^^^^^

SyntaxError: Unexpected token import
    at createScript (vm.js:80:10)
    at Object.runInThisContext (vm.js:152:10)
    at Module._compile (module.js:624:28)
    at Object.Module._extensions..js (module.js:671:10)
    at Module.load (module.js:573:32)
    at tryModuleLoad (module.js:513:12)
    at Function.Module._load (module.js:505:3)
    at Function.Module.runMain (module.js:701:10)
    at startup (bootstrap_node.js:194:16)
    at bootstrap_node.js:618:3

solution

# npm package installation
npm install --save-dev babel-preset-env babel-cli es-collections

# .babelrc setup
$ cat .babelrc
{
  "presets": [
    ["env", {
      "targets": {
        "node": "current"
      }
    }]
  ]
}

# execution with node
$ npx babel ex.js --out-file ex-new.js
$ node ex-new.js
Successfully Imported

# or execution with babel-node
$ babel-node ex.js
Successfully Imported

Answer 12

@jovi all you need to do is add .babelrc file like this:

{
  "plugins": [
    "transform-strict-mode",
    "transform-es2015-modules-commonjs",
    "transform-es2015-spread",
    "transform-es2015-destructuring",
    "transform-es2015-parameters"
  ]
}

and install these plugins as devdependences with npm.

then try babel-node ***.js again. hope this can help you.

Answer 13

In your app, you must declare your require() modules, not using the 'import' keyword:

const app = require("example_dependency");

Then, create a .babelrc file:

{
"presets": [ 
    ["es2015", { "modules": false }]
]
}

Then, in your gulpfile, be sure to declare your require() modules:

var gulp = require("gulp");