infra: add hyperview watch mode for demo app (#32)

With this PR we can develop hyperview features in watch mode. Changes in src should directly get reflected in the demo app with the `build:demo` command running. This also saves us from the "duplicate modules" error which happens if we're using `yarn link`.

Also updated readme.

README.md

@@ -1,72 +1,101 @@
 [![logo](./demo/assets/images/icon_small.png)](https://hyperview.org)
+
 # Native mobile apps, as easy as creating a website.
 
 [Hyperview](https://hyperview.org) is a new hypermedia format and React Native client for developing server-driven mobile apps.
 
 - **Serve your app as XML**: On the web, pages are rendered in a browser by fetching HTML content from a server. With Hyperview, screens are rendered in your mobile app by fetching Hyperview XML (HXML) content from a server. HXML's design reflects the UI and interaction patterns of today's mobile interfaces.
 - **Work with any backend web technology**: Use battle-tested web technologies like Django, Rails, or Node. Any HTTP server can host a Hyperview app. You can even deploy your app as a collection of static XML files if you want!
 - **Update your apps instantly by deploying your backend**: Say goodbye to slow release cycles and long app store review times. With Hyperview, your backend controls your app's layout, content, and available actions. The means you can update any aspect of your app with a server-side change. True CI/CD is finally attainable for mobile development.
-- **Forget about API versioning and backwards compatibility**:  Unlike traditional native apps, every user always runs the most recent version of your code. With no version fragmentation, you can be more productive by eliminating the need to support and maintain older app versions.
+- **Forget about API versioning and backwards compatibility**: Unlike traditional native apps, every user always runs the most recent version of your code. With no version fragmentation, you can be more productive by eliminating the need to support and maintain older app versions.
 
 See the [Hyperview website](https://hyperview.org) for more information about Hyperview and Hyperview XML.
 
 ## Hyperview XML
+
 - See examples of how to create rich, interactive apps with Hyperview XML [here](https://hyperview.org/docs/example_navigation)
 - See the full references for Hyperview XML [here](https://hyperview.org/docs/reference_screen)
 
 ## Hyperview React Native Client
+
 [![CircleCI](https://circleci.com/gh/Instawork/hyperview.svg?style=svg)](https://circleci.com/gh/Instawork/hyperview)
 
 This repo contains a React Native implementation of the Hyperview Client. It can either be integrated into an existing React Native app, or used to create a self-contained RN app.
 
 ### Requirements
+
 The Hyperview client only has two required dependencies:
+
 - url-parse 1.4.3
 - xmldom 0.1.27
 
 More importantly, the client is designed to be incorporated into an existing React Native project, and thus has the following peer dependencies:
+
 - react >= 16.2.0
 - react-native >= 0.52.2
 - react-native-keyboard-aware-scrollview 2.0.0
 
 ### Getting Started
-This repo contains an example XML server that serves Hyperview XML to showcase the available features. 
+
+This repo contains an example XML server that serves Hyperview XML to showcase the available features.
 It also contains a demo Expo project that can connect to the example XML server, or any other Hyperview endpoint.
 
 #### 1. Run the example server
+
 From the repo root directory:
+
 ```
 yarn
 yarn test:xmlserver
 ```
-This will start an HTTP server listening on port 8085. 
 
+This will start an HTTP server listening on port 8085.
 
 #### 2. Start the demo app
+
 In a separate shell, install the demo dependencies and start the development server. From the repo root directory:
+
 ```
 cd demo
 yarn
 ```
 
 The next step depends on whether you want to run the demo app in the iOS simulator, on an Android Virtual Device, or on a physical mobile device.
 
+While developing hyperview features using the demo app you may also run hyperview builds in watch mode. This will directly reflect the changes in the `demo/` app as you make changes to hyperview `src`. From the project root run:
+
+```sh
+yarn build:demo
+```
+
+> **Tip**
+>
+> You may stop this with <kbd>Ctrl</kbd> + <kbd>C</kbd>
+
 ##### Running on the iOS simulator
+
 From the `demo/` directory:
+
 ```
 yarn ios
 ```
+
 This will open the iOS simulator and install the demo app in the simulator. It will then start the Expo development server to load the demo app.
 
 ##### Running on an Android Virtual Device
+
 From the `demo/` directory:
+
 ```
 yarn android
 ```
+
 This will open an AVD and install the demo app in the emulator. It will then start the Expo development server to load the demo app.
 
 ##### Running on a physical device
+
 On your physical mobile device, install the Expo client
+
 - [iOS App Store](https://itunes.apple.com/us/app/expo-client/id982107779?mt=8)
 - [Google Play Store](https://play.google.com/store/apps/details?id=host.exp.exponent)
 
@@ -75,23 +104,26 @@ Make sure your mobile device and development machine are connected to the same n
 Open [/demo/navigation/AppNavigator.js](/demo/navigation/AppNavigator.js) in a text editor. In `initialRouteParams`, replace the host in the url (`http://0.0.0.0:8085/index.xml`) with the IP of your machine. This is needed in order for your physical device to be able to request the example XML files from your development machine.
 
 From the `demo/` directory on your development machine:
+
 ```
 yarn start
 ```
+
 This command will start an Expo development server and open a webpage (http://localhost:19002). This webpage will display a QR code.
 
 - On your iOS device, open the Camera app and point it at the QR code on your screen. The Camera app should show an "Open in Expo" notification. Tap this notification.
 - On your Android device, use the Expo app to scan the QR code on your screen.
 
-
 #### 3. You're all set!
+
 Whether you're using a physical device or simulator, you should now see a Hyperview screen rendered from the example server:
 
 ![example](./demo/assets/images/example.gif)
 
 The example server simply serves files from the [./examples](/examples) directory. You can modify or add files in [./examples](/examples) and the server will update without restarting.
 
 #### Troubleshooting
+
 > This version of the Expo app is out of date. Uninstall the app and run again to upgrade.
 
 If you see this warning message on the Expo development server webpage, you need to uninstall the Expo app from the simulator or physical device and install the latest version. On a physical device, this means getting the latest version from an app store. In the simulator or AVD, this means uninstalling and re-running `yarn ios` or `yarn android`.

demo/yarn.lock

@@ -2790,9 +2790,10 @@ http-signature@~1.2.0:
     jsprim "^1.2.2"
     sshpk "^1.7.0"
 
-hyperview@^0.6.0:
-  version "0.6.0"
-  resolved "https://registry.yarnpkg.com/hyperview/-/hyperview-0.6.0.tgz#57516de1c93caaaf0b477db0339ee6a023818e70"
+hyperview@^0.9.0:
+  version "0.9.0"
+  resolved "https://registry.yarnpkg.com/hyperview/-/hyperview-0.9.0.tgz#2257400027da6e98e288efce52477cd2a0b1aae3"
+  integrity sha512-CdWtalGis7Ge3YFH76uFI4Uq4ETneySVgT8lGvgStnQY0H8Q8YvkprRbZCiv865Ixgh3Tjft8gFDRHab/99iyw==
   dependencies:
     url-parse "1.4.3"
     xmldom "0.1.27"

package.json

@@ -21,6 +21,7 @@
   },
   "scripts": {
     "build": "babel src --out-dir lib",
+    "build:demo": "babel src --out-dir demo/node_modules/hyperview/lib --watch",
     "generate": "babel-node ./scripts/generate",
     "preversion": "yarn test && yarn build",
     "prettify": "pretty-quick",