sass-loader not working with webpack + react + gro

Question

I'm trying to get started with webpack and Grommet working together. I'm following this tutorial: https://github.com/grommet/grommet-standalone but I'm getting the following error:

ERROR in ./src/app/index.js
Module not found: Error: Can't resolve 'grommet/scss/vanilla/index' in '/home/john/Development/Work/Utilities/react_practice/test_app/src/app'
 @ ./src/app/index.js 31:0-37
 @ multi library

Clearly it's looking for the scss file files in the source directory rather than node_modules - but I have no idea whats causing the error or how to fix it.

I'm using this sass loader: https://github.com/jtangelder/sass-loader

And I'm using webpack 2.10 because of this: https://stackoverflow.com/a/39608145/1596288

Additionally, these are my webpack.config.babel.js and index.js files:

import webpack from 'webpack';

module.exports = {
    entry: {
        library: './src/app/index.js',
    },

    output: {
        library: 'bundle',
        libraryTarget: 'umd',
        filename: 'bundle.js',
        path: './public/dist'
    },

    devServer : {
        inline: true,
        contentBase: './public',
        port: 8100
    },

    module: {
        loaders: [
            {
                test: /\.jsx?$/,
                loader: 'babel-loader',
                exclude: /node_modules/,
                query: {
                    presets: ['es2015', 'react']
                }
            },

            {
                test: /\.scss$/,
                loader: 'style!css!sass?outputStyle=compressed'
            }
        ]
    },

    sassLoader: {
        sourceMap: true,
        includePaths: [
            './node_modules',
            './node_modules/grommet/node_modules'
        ]
    }
}

and ...

import Header from 'grommet/components/Header';
import Title from 'grommet/components/Title';
import Box from 'grommet/components/Box';
import Search from 'grommet/components/Search';
import Menu from 'grommet/components/Menu';
import Anchor from 'grommet/components/Anchor';
import Actions from 'grommet/components/icons/base/Actions'

import 'grommet/scss/vanilla/index';

import React from 'react'
import { render } from 'react-dom'

const TesterComponent = () => (
   <Header>
        <Title>
            Sample Title
        </Title>

        <Box flex={true}
        justify='end'
        direction='row'
        responsive={false}>
            <Search inline={true}
            fill={true}
            size='medium'
            placeHolder='Search'
            dropAlign={{"right": "right"}} />

            <Menu icon={<Actions />}
            dropAlign={{"right": "right"}}>
                <Anchor href='#'
                    className='active'>
                    First
                </Anchor>
                <Anchor href='#'>
                    Second
                </Anchor>
                <Anchor href='#'>
                    Third
                </Anchor>
            </Menu>
        </Box>
    </Header>
)


render (
    <TesterComponent />,
    document.getElementById('root')
)

Answer 1

try this

{
        test: /\.scss$/,
        loader: ExtractTextPlugin.extract('style-loader', "css-loader!postcss-loader!sass-loader")
      },

Answer 2

Managed to fix the issue by firstly modifiying my webpack.config.babel.js to the following:

import webpack from 'webpack';

module.exports = {
entry: {
    library: './src/app/index.js',
},

output: {
    library: 'bundle',
    libraryTarget: 'umd',
    filename: 'bundle.js',
    path: './public/dist'
},

devServer : {
    inline: true,
    contentBase: './public',
    port: 8100
},

resolve: {
    extensions: ['', '.js', '.scss', '.css']
},

module: {
    loaders: [
        {
            test: /\.jsx?$/,
            loader: 'babel-loader',
            exclude: /node_modules/,
            query: {
                presets: ['es2015', 'react']
            }
        },

        {
            test: /\.scss$/,
            loader: 'style-loader!css-loader!sass-loader?outputStyle=compressed'
        }
    ]
},

sassLoader: {
    includePaths: [
        './node_modules',
        './node_modules/grommet/node_modules'
    ]
}

}

Make sure you have the following libs installed too:

sudo npm install style-loader --save-dev
sudo npm install css-loader --save-dev
sudo npm install sass-loader --save-dev