Add HMR with webpack-dev-server

Signed-off-by: Julius Härtl <jus@bitgrid.net>

webpack.hot.js

@@ -0,0 +1,26 @@
+const webpack = require('webpack');
+const merge = require('webpack-merge');
+const dev = require('./webpack.dev.js');
+
+module.exports = merge(dev, {
+	devServer: {
+		hot: true,
+		port: 3000,
+		/**
+		 * This makes sure the main entrypoint is written to disk so it is
+		 * loaded by Nextcloud though our existing addScript calls
+		 */
+		writeToDisk: (filePath) => {
+			return /deck\.js$/.test(filePath);
+		},
+		headers: {
+			'Access-Control-Allow-Origin': '*'
+		}
+	},
+	plugins: [
+		new webpack.DefinePlugin({
+			'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV),
+			'process.env.HOT': true
+		})
+	]
+})