Optimize demo (#2681)

config/webpack.js

@@ -0,0 +1,46 @@
+const webpack = require("webpack");
+const path = require("path");
+const BabelMinifyPlugin = require("babel-minify-webpack-plugin");
+
+module.exports.plugins = [
+  // Ignore moment.js locales
+  new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/),
+  // Color.js is bloated, it contains all color definitions for all material color sets.
+  new webpack.NormalModuleReplacementPlugin(
+    /@polymer\/paper-styles\/color\.js$/,
+    path.resolve(__dirname, "../src/util/empty.js")
+  ),
+  // Ignore roboto pointing at CDN. We use local font-roboto-local.
+  new webpack.NormalModuleReplacementPlugin(
+    /@polymer\/font-roboto\/roboto\.js$/,
+    path.resolve(__dirname, "../src/util/empty.js")
+  ),
+];
+
+module.exports.minimizer = [
+  // Took options from Polymer build tool
+  // https://github.com/Polymer/tools/blob/master/packages/build/src/js-transform.ts
+  new BabelMinifyPlugin(
+    {
+      // Disable the minify-constant-folding plugin because it has a bug relating
+      // to invalid substitution of constant values into export specifiers:
+      // https://github.com/babel/minify/issues/820
+      evaluate: false,
+
+      // TODO(aomarks) Find out why we disabled this plugin.
+      simplifyComparisons: false,
+
+      // Prevent removal of things that babel thinks are unreachable, but sometimes
+      // gets wrong: https://github.com/Polymer/tools/issues/724
+      deadcode: false,
+
+      // Disable the simplify plugin because it can eat some statements preceeding
+      // loops. https://github.com/babel/minify/issues/824
+      simplify: false,
+
+      // This is breaking ES6 output. https://github.com/Polymer/tools/issues/261
+      mangle: false,
+    },
+    {}
+  ),
+];