"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?

Solution 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"]
}

Solution 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/

Solution 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.

Solution 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.

Solution 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

View more solutions

Comments

[Scott Sauyet]

@FelixKling: Although the answer at the linked question does certainly also answer this question, it's hard to see this question as a duplicate of that one. In any case, I was glad to have this one here, as Google brought me directly here because the described syntax error exactly matched what I saw. I'm honestly glad that the OP posted this rather than searched for a somewhat related question with an answer that happened to fit.

[ChuckJHardy]

npm i --save-dev babel-cli Fixed it for me...

[T.W.R. Cole]

I vote to unmark this as a duplicate, I feel this is a separate question.

[Dan Dascalescu]

This is not a duplicate. One other solution I would like to post is to double check you have this plugin in .babelrc: "transform-es2015-modules-commonjs".

[Stijn de Witt]

Duplicates are (should be) ok. It's an important part of how humans work. What @ScottSauyet says is one of the reasons. Different explanations with different perspectives is another. This whole 'duplicate hunt' feels very unhelpful to me as a reguar visitor for years. I wish it would stop.

[Natesh bhat]

For newer versions of react , use the new babel modules : stackoverflow.com/a/53927497/6665568 . It has better error messages and supports new features of react.

[Jagtesh Chadha]

Good answer. Unfortunately, you still need to use require() and can't use import for npm packages.

[FuzzY]

I use babel-node together with es2015 and react presets. Same error.

[Scott Sauyet]

I'm not sure if things have changed in the last few months. But it worked fine for me.

[still_dreaming_1]

Dosn't work. Yes that is needed, but it doesn't make import work.

[joezen777]

For me it was a simple fix. I was caught in tunnel vision trying to adapt code from one react/babel project into another es5 project and upgrade to es6 syntax at the same time. In my package.json under scripts, I forgot to replace "node run" with "babel-node run.js". Yeah, I feel sheepish. :)

[a0s]

npm install babel-preset-latest --save-dev; echo '{ "presets": ["latest"] }' > .babelrc

[rodrigo-silveira]

Works as prescribed. Node v6.2.9, babel-cli v6.18.0

[omerts]

For those of you that it doesn't work for, don't forget to install the preset: npm install babel-preset-es2015 --save-dev

[Sylver]

sorry, but doesn't work. with babel-presets-* installed in devDependencies and .babelrc configured to use them

[ronen]

latest recommendation from the babel folks is to use babel-preset-env which detects which polyfills to run, rather than babel-preset-node*. In .babelrc use: { "presets": [ ["env", { "targets": { "node": "current" } }] ] }

[Joe Heyming]

Don't forget to tell them to update babel-preset-es2015. 6.18.0 did not work for me, but 6.24 does

[Jonas Drotleff]

This is an easy workaround that can be used for development. Although for production you should always compile your es5 code.

[dipole_moment]

Did not work unfortunatley. Unexpected token import.

[Craig Gjerdingen]

I know this is going to sound too simple, but if you have tried everything and it still isn't working, double check the spelling of everything. Pretty easy to call it .bablerc, instead of .babelrc of some such mistake! And you will continue to get the “unexpected token import” message.

[Dmytro]

wait... is this what i think it is? a few months ago i had this dream that javascript/perl/any language could be extended without updates by custom extra parsing of the existing language in the same language. Is this what's going on here???

[Maksim Yegorov]

Make sure that the babel command is in your search path. Here's a slight variation. package.json: { "scripts": { "transpile": "./node_modules/.bin/babel src -d lib" }, "devDependencies": { "babel-cli": "^6.24.1", "babel-preset-env": "^1.6.0" } } .babelrc: { "presets": ["env"] }

[Rodrigo]

JS ecosystem is so easy

[A. K.]

After this I started getting the error (unrecognized token '<'): server.js: Unexpected token (37:12) 35 | const initialState = store.getState(); 36 | const componentHTML = renderToString( > 37 | <Provider store={store}> | ^ 38 | <RouterContext {...props} /> 39 | </Provider>, 40 | );

[gkarthiks]

Excellent answer. But in the scripts, you can put something like below. So you can use in any file. "scripts": { "build": "babel src -d dist", "start": "node dist/index.js" }

[jcollum]

Is there a way to do this with the CLI?