Field 'browser' doesn't contain a vali

Question

I've started using webpack2 (to be precise, v2.3.2) and after re-creating my config I keep running into an issue that I can't seem to solve. I get (sorry in advance for ugly dump):

ERROR in ./src/main.js
Module not found: Error: Can't resolve 'components/DoISuportIt' in '[absolute path to my repo]/src'
resolve 'components/DoISuportIt' in '[absolute path to my repo]/src'
  Parsed request is a module
  using description file: [absolute path to my repo]/package.json (relative path: ./src)
    Field 'browser' doesn't contain a valid alias configuration
    aliased with mapping 'components': '[absolute path to my repo]/src/components' to '[absolute path to my repo]/src/components/DoISuportIt'
      using description file: [absolute path to my repo]/package.json (relative path: ./src)
        Field 'browser' doesn't contain a valid alias configuration
      after using description file: [absolute path to my repo]/package.json (relative path: ./src)
        using description file: [absolute path to my repo]/package.json (relative path: ./src/components/DoISuportIt)
          as directory
            [absolute path to my repo]/src/components/DoISuportIt doesn't exist
          no extension
            Field 'browser' doesn't contain a valid alias configuration
            [absolute path to my repo]/src/components/DoISuportIt doesn't exist
          .js
            Field 'browser' doesn't contain a valid alias configuration
            [absolute path to my repo]/src/components/DoISuportIt.js doesn't exist
          .jsx
            Field 'browser' doesn't contain a valid alias configuration
            [absolute path to my repo]/src/components/DoISuportIt.jsx doesn't exist
[[absolute path to my repo]/src/components/DoISuportIt]
[[absolute path to my repo]/src/components/DoISuportIt]
[[absolute path to my repo]/src/components/DoISuportIt.js]
[[absolute path to my repo]/src/components/DoISuportIt.jsx]

package.json

{
  "version": "1.0.0",
  "main": "./src/main.js",
  "scripts": {
    "build": "webpack --progress --display-error-details"
  },
  "devDependencies": {
    ...
  },
  "dependencies": {
    ...
  }
}

In terms of the browser field it's complaining about, the documentation I've been able to find on this is: package-browser-field-spec. There is also webpack documentation for it, but it seems to have it turned on by default: aliasFields: ["browser"]. I tried adding a browser field to my package.json but that didn't seem to do any good.

webpack.config.js

import path from 'path';
const source = path.resolve(__dirname, 'src');

export default {
  context: __dirname,
  entry: './src/main.js',
  output: {
    path: path.resolve(__dirname, 'dist'),
    filename: '[name].js',
  },
  resolve: {
    alias: {
      components: path.resolve(__dirname, 'src/components'),
    },
    extensions: ['.js', '.jsx'],
  },
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        include: source,
        use: {
          loader: 'babel-loader',
          query: {
            cacheDirectory: true,
          },
        },
      },
      {
        test: /\.css$/,
        include: source,
        use: [
          { loader: 'style-loader' },
          {
            loader: 'css-loader',
            query: {
              importLoader: 1,
              localIdentName: '[path]___[name]__[local]___[hash:base64:5]',
              modules: true,
            },
          },
        ],
      },
    ],
  },
};

src/main.js

import DoISuportIt from 'components/DoISuportIt';

src/components/DoISuportIt/index.jsx

export default function() { ... }

For completeness, .babelrc

{
  "presets": [
    "latest",
    "react"
  ],
  "plugins": [
    "react-css-modules"
  ],
  "env": {
    "production": {
      "compact": true,
      "comments": false,
      "minified": true
    }
  },
  "sourceMaps": true
}

What am I doing wrong/missing?

Answer 1

Turned out to be an issue with Webpack just not resolving an import - talk about horrible horrible error messages :(

// Had to change
import DoISuportIt from 'components/DoISuportIt';

// To (notice the missing `./`)
import DoISuportIt from './components/DoISuportIt';

Answer 2

For everyone with Ionic: Updating to the latest @ionic/app-scripts version gave a better error message.

npm install @ionic/app-scripts@latest --save-dev

It was a wrong path for styleUrls in a component to a non-existing file. Strangely it gave no error in development.

Answer 3

I'm building a React server-side renderer and found this can also occur when building a separate server config from scratch. If you're seeing this error, try the following:

1. Make sure your "entry" value is properly pathed relative to your "context" value. Mine was missing the preceeding "./" before the entry file name.
2. Make sure you have your "resolve" value included. Your imports on anything in node_modules will default to looking in your "context" folder, otherwise.

Example:

const serverConfig = {
name: 'server',
context: path.join(__dirname, 'src'),
entry: {serverEntry: ['./server-entry.js']},
output: {
    path: path.join(__dirname, 'public'),
    filename: 'server.js',
    publicPath: 'public/',
    libraryTarget: 'commonjs2'
},
module: {
    rules: [/*...*/]
},
resolveLoader: {
    modules: [
        path.join(__dirname, 'node_modules')
    ]
},
resolve: {
    modules: [
        path.join(__dirname, 'node_modules')
    ]
}
};