build: group webpack & ignore dist & support yarn1.x (#2551)

.webpack/webpack.config.e2e.babel.js

@@ -0,0 +1,37 @@
+import baseConfig, { resolveRoot } from './webpack.config.base';
+import { merge } from 'webpack-merge';
+
+export default merge(baseConfig, {
+  mode: 'development',
+  entry: {
+    mermaid: './src/mermaid.js',
+    e2e: './cypress/platform/viewer.js',
+    'bundle-test': './cypress/platform/bundle-test.js',
+  },
+  output: {
+    globalObject: 'window',
+  },
+  devServer: {
+    compress: true,
+    port: 9000,
+    static: [
+      { directory: resolveRoot('cypress', 'platform') },
+      { directory: resolveRoot('dist') },
+      { directory: resolveRoot('demos') },
+    ],
+  },
+  externals: {
+    mermaid: 'mermaid',
+  },
+  module: {
+    rules: [
+      {
+        test: /\.js$/,
+        exclude: /node_modules/,
+        use: {
+          loader: 'babel-loader',
+        },
+      },
+    ],
+  },
+});