“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

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 2

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 3

@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 4

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 5

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 6

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