docs: document new features

docs/guide/browser-compatibility.md

@@ -42,7 +42,25 @@ See [@babel-preset/env docs](https://new.babeljs.io/docs/en/next/babel-preset-en
 
 ## Modern Mode
 
-> TODO
+With Babel we are able to leverage all the newest language features in ES2015+, but that also means we have to ship transpiled and polyfilled bundles in order to support older browsers. These transpiled bundles often more verbose than the original native ES2015+ code, and also parses and runs slower. Given that today a good majority of the modern browsers have decent support for native ES2015, it is a waste that we have to ship heavier and less efficient code to those browsers just because we have to support older ones.
+
+Vue CLI offers a "Modern Mode" to help you solve this problem. When building for production with the following command:
+
+``` bash
+vue-cli-service build --modern
+```
+
+Vue CLI will produce two versions of your app: one modern bundle targeting modern browsers that support [ES modules](https://jakearchibald.com/2017/es-modules-in-browsers/), and one legacy bundle targeting older browsers that do not.
+
+The cool part though is that there are no special deployment requirements. The generated HTML file automatically employs the techniques discussed in [Phillip Walton's excellent post](https://philipwalton.com/articles/deploying-es2015-code-in-production-today/):
+
+- The modern bundle is loaded with `<script type="module">`, in browsers that support it; they are also preloaded using `<link rel="modulepreload">` instead.
+
+- The legacy bundle is loaded with `<script nomodule>`, which is ignored by browsers that support ES modules.
+
+- A fix for `<script nomodule>` in Safari 10 is also automatically injected.
+
+For a Hello World app, the modern bundle is already 16% smaller. In production, the modern bundle will typically result in significantly faster parsing and evaluation, improving your app's loading performance.
 
 [autoprefixer]: https://github.com/postcss/autoprefixer
 [babel-preset-env]: https://new.babeljs.io/docs/en/next/babel-preset-env.html

docs/guide/cli-service.md

@@ -55,16 +55,26 @@ Usage: vue-cli-service build [options] [entry|pattern]
 
 Options:
 
-  --mode    specify env mode (default: production)
-  --dest    specify output directory (default: dist)
-  --target  app | lib | wc | wc-async (default: app)
-  --name    name for lib or web-component mode (default: "name" in package.json or entry filename)
-  --watch   watch for changes
+  --mode        specify env mode (default: production)
+  --dest        specify output directory (default: dist)
+  --modern      build app targeting modern browsers with auto fallback
+  --target      app | lib | wc | wc-async (default: app)
+  --name        name for lib or web-component mode (default: "name" in package.json or entry filename)
+  --no-clean    do not remove the dist directory before building the project
+  --report      generate report.html to help analyze bundle content
+  --report-json generate report.json to help analyze bundle content
+  --watch       watch for changes
 ```
 
 `vue-cli-service build` produces a production-ready bundle in the `dist/` directory, with minification for JS/CSS/HTML and auto vendor chunk splitting for better caching. The chunk manifest is inlined into the HTML.
 
-It is also possible to build any component(s) inside your project as a library or as web components. See [Build Targets](./build-targets.md) for more details.
+There are a few useful flags:
+
+- `--modern` builds your app using [Modern Mode](./browser-compatibility.md#modern-mode), shipping native ES2015 code to modern browsers that support it, with auto fallback to a legacy bundle.
+
+- `--target` allows you to build any component(s) inside your project as a library or as web components. See [Build Targets](./build-targets.md) for more details.
+
+- `--report` and `--report-json` will generate reports based on your build stats that can help you analyze the size of the modules included in your bundle.
 
 ## vue-cli-service inspect
 

packages/@vue/cli-service/lib/commands/serve.js

@@ -17,6 +17,7 @@ module.exports = (api, options) => {
     usage: 'vue-cli-service serve [options] [entry]',
     options: {
       '--open': `open browser on server start`,
+      '--copy': `copy url to clipboard on server start`,
       '--mode': `specify env mode (default: development)`,
       '--host': `specify host (default: ${defaults.host})`,
       '--port': `specify port (default: ${defaults.port})`,