webpack.config.js

// webpack.config.js
const webpack = require('webpack')
const path = require('path')
const WebpackShellPlugin = require('webpack-shell-plugin')

const config = {
    context: path.resolve(__dirname, 'src'),
    entry: './_main.js',
    output: {
        path: path.resolve(__dirname, 'dist'),
        filename: 'leaflet.canvaslayer.field.js'
    },
    module: {
        rules: [
            {
                enforce: 'pre',
                test: /\.js$/,
                include: path.resolve(__dirname, 'src'),
                exclude: '/node_modules/',
                loader: "eslint-loader"
            },
            {
                test: /\.js$/,
                include: path.resolve(__dirname, 'src'),
                exclude: '/node_modules/',
                use: [
                    {
                        loader: 'babel-loader',
                        options: {
                            presets: [
                        ['es2015', {
                                    modules: false
                        }]
                    ]
                        }
                }]
            }
        ]
    },
    plugins: [
    new WebpackShellPlugin({
            onBuildStart: ['echo "Webpack Start"'],
            onBuildEnd: ['node copy-to-examples.js']
        })
  ]
}

module.exports = config