使用ES7 async / await与node，webpack和babel-loader时出错

Question

I'm trying to use javascript ES7 syntax on the server using node.js with webpack and babel-loader (es2015 + stage-0 presets). I've gotten it to work with babel-node but when I run webpack I get the following error at the async keyword (9:22 is after the async keyword):

ERROR in ./src/server.js Module parse failed: C:\dev\node-async-sample\src\server.js 
Unexpected token (9:22) You may need an appropriate loader to handle this file type. 
SyntaxError: Unexpected token (9:22)

I've put the code on github at https://github.com/qubitron/node-async-sample , any ideas on how to get this to work?

Here is the relevant snippet from src/server.js:

import express from 'express';
import http from 'request-promise';

let server = express();

server.get('/', async function(request, response) {
    let result = await http('http://www.google.com');
    response.send(result);
});

.babelrc:

{
  "presets": [
    "es2015",
    "node5",
    "stage-0"
  ],
  "plugins": [
    "transform-runtime"
  ]
}

and webpack.config.js:

module.exports = {
  entry: [
    'babel-polyfill',
    './src/server.js'
  ],
  output: {
    path: __dirname + '/dist',
    filename: 'server_bundle.js'
  },
  resolve: {
      extensions: ['', '.js', '.jsx']
  },
  module: {
    loaders: [
      {
        test: /\.jsx?$/,
        include: __dirname + '/src',
        loader: 'babel-loader'
      }
    ]
  }
};

I saw a similar issue here but it has a different error message and was fixed in babel:master: ES7 async await functions with babel-loader not working

Answer 1

Your src path was incorrect. You should never (like never :)) join pathes using string concatenation there is path.join for that.

{
   test: /\.jsx?$/,
   include: path.join(__dirname, 'src'),
   loader: 'babel-loader'
}

BTW, this will fix parsing issue but you still gonna need to handle .json file loading by adding corresponding extension to resolve section and using json-loader

{ test: /\.json$/, loader: 'json-loader' }

Also you'll need to handle missing modules warning. For example fs and net .

So I do recommend you to use babel-cli to precompile server code.

babel src --out-dir dist