MyCrypto/webpack_config/webpack.dev.js

'use strict'
process.env.NODE_ENV = 'development'
process.env.REACT_WEBPACK_ENV = 'dev'

const webpack = require('webpack')
const base = require('./webpack.base')
const FriendlyErrors = require('friendly-errors-webpack-plugin')

base.devtool = 'eval-source-map'
base.module.loaders.push({
        test: /\.css$/,
        loaders: ['style-loader', 'css-loader', 'resolve-url-loader']
    },
    {
        test: /\.scss$/,
        loaders: ['style-loader', 'css-loader', 'resolve-url-loader', 'sass-loader']
    },
    {
        test: /\.less$/,
        loaders: ['style-loader', 'css-loader', 'resolve-url-loader', 'less-loader']
    })

base.plugins.push(
    new webpack.DefinePlugin({
        'process.env.NODE_ENV': JSON.stringify('development')
    }),
    new webpack.HotModuleReplacementPlugin(),
    new webpack.NoEmitOnErrorsPlugin(),
    new FriendlyErrors()
)

module.exports = base