CLI: Add support for project templates

Summary:
Currently it is not trivial for people to get started with React Native. `react-native init MyApp` just creates a simple app with a single screen. People have to spend time figuring out how to add more screens, or how to accomplish very basic tasks such as rendering a list of data or handling text input.

Let's add an option: `react-native init --template navigation` - this creates a "starter" app which can be easily tweaked into the actual app the person wants to build.

**Test plan (required)**

- Checked that 'react-native init MyApp' still works as before:

<img width="487" alt="screenshot 2017-02-02 16 56 28" src="https://cloud.githubusercontent.com/assets/346214/22559344/b2348ebe-e968-11e6-9032-d1c33216f490.png">

<img width="603" alt="screenshot 2017-02-02 16 58 04" src="https://cloud.githubusercontent.com/assets/346214/22559370/c96a2ca6-e968-11e6-91f7-7afb967920fc.png">

- Ran 'react-native init MyNavApp --template'. This prints the available templates:

```
$ react-native init MyNavApp
Closes #12170

Differential Revision: D4516241

Pulled By: mkonicek

fbshipit-source-id: 8ac081157919872e92947ed64ea64fb48078614d

local-cli/generator/templates.js

@@ -0,0 +1,112 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+'use strict';
+
+const copyProjectTemplateAndReplace = require('./copyProjectTemplateAndReplace');
+const execSync = require('child_process').execSync;
+const fs = require('fs');
+const path = require('path');
+
+const availableTemplates = {
+  navigation: 'HelloNavigation',
+};
+
+function listTemplatesAndExit(newProjectName, options) {
+  if (options.template === true) {
+    // Just listing templates using 'react-native init --template'.
+    // Not creating a new app.
+    // Print available templates and exit.
+    const templateKeys = Object.keys(availableTemplates);
+    if (templateKeys.length === 0) {
+      // Just a guard, should never happen as long availableTemplates
+      // above is defined correctly :)
+      console.log(
+        'There are no templates available besides ' +
+        'the default "Hello World" one.'
+      );
+    } else {
+      console.log(
+        'The available templates are:\n' +
+        templateKeys.join('\n') +
+        '\nYou can use these to create an app based on a template, for example: ' +
+        'you could run: ' +
+        'react-native init ' + newProjectName + ' --template ' + templateKeys[0]
+      );
+    }
+    // Exit 'react-native init'
+    return true;
+  }
+  // Continue 'react-native init'
+  return false;
+}
+
+/**
+ * @param newProjectName For example 'AwesomeApp'.
+ * @param templateKey Template to use, for example 'navigation'.
+ * @param yarnVersion Version of yarn available on the system, or null if
+ *                    yarn is not available. For example '0.18.1'.
+ */
+function createProjectFromTemplate(destPath, newProjectName, templateKey, yarnVersion) {
+  // Expand the basic 'HelloWorld' template
+  copyProjectTemplateAndReplace(
+    path.resolve('node_modules', 'react-native', 'local-cli', 'templates', 'HelloWorld'),
+    destPath,
+    newProjectName
+  );
+
+  if (templateKey !== undefined) {
+    // Keep the files from the 'HelloWorld' template, and overwrite some of them
+    // with the specified project template.
+    // The 'HelloWorld' template contains the native files (these are used by
+    // all templates) and every other template only contains additional JS code.
+    // Reason:
+    // This way we don't have to duplicate the native files in every template.
+    // If we duplicated them we'd make RN larger and risk that people would
+    // forget to maintain all the copies so they would go out of sync.
+    const templateName = availableTemplates[templateKey];
+    if (templateName) {
+      copyProjectTemplateAndReplace(
+        path.resolve(
+          'node_modules', 'react-native', 'local-cli', 'templates', templateName
+        ),
+        destPath,
+        newProjectName
+      );
+    } else {
+      throw new Error('Uknown template: ' + templateKey);
+    }
+
+    // Add dependencies:
+
+    // dependencies.json is a special file that lists additional dependencies
+    // that are required by this template
+    const dependenciesJsonPath = path.resolve(
+      'node_modules', 'react-native', 'local-cli', 'templates', templateName, 'dependencies.json'
+    );
+    if (fs.existsSync(dependenciesJsonPath)) {
+      console.log('Adding dependencies for the project...');
+      const dependencies = JSON.parse(fs.readFileSync(dependenciesJsonPath));
+      for (let depName in dependencies) {
+        const depVersion = dependencies[depName];
+        const depToInstall = depName + '@' + depVersion;
+        console.log('Adding ' + depToInstall + '...');
+        if (yarnVersion) {
+          execSync(`yarn add ${depToInstall}`, {stdio: 'inherit'});
+        } else {
+          execSync(`npm install ${depToInstall} --save --save-exact`, {stdio: 'inherit'});
+        }
+      }
+    }
+  }
+}
+
+module.exports = {
+  listTemplatesAndExit,
+  createProjectFromTemplate,
+};

local-cli/init/init.js

@@ -8,7 +8,10 @@
  */
 'use strict';
 
-const copyProjectTemplateAndReplace = require('../generator/copyProjectTemplateAndReplace');
+const {
+  listTemplatesAndExit,
+  createProjectFromTemplate,
+} = require('../generator/templates');
 const execSync = require('child_process').execSync;
 const fs = require('fs');
 const minimist = require('minimist');
@@ -23,15 +26,15 @@ const yarn = require('../util/yarn');
  * @param projectDir Templates will be copied here.
  * @param argsOrName Project name or full list of custom arguments
  *                   for the generator.
+ * @param options Command line options passed from the react-native-cli directly.
+ *                E.g. `{ version: '0.43.0', template: 'navigation' }`
  */
 function init(projectDir, argsOrName) {
-  console.log('Setting up new React Native app in ' + projectDir);
-
   const args = Array.isArray(argsOrName)
     ? argsOrName // argsOrName was e.g. ['AwesomeApp', '--verbose']
     : [argsOrName].concat(process.argv.slice(4)); // argsOrName was e.g. 'AwesomeApp'
 
-  // args array is e.g. ['AwesomeApp', '--verbose']
+  // args array is e.g. ['AwesomeApp', '--verbose', '--template', 'navigation']
   if (!args || args.length === 0) {
     console.error('react-native init requires a project name.');
     return;
@@ -40,7 +43,14 @@ function init(projectDir, argsOrName) {
   const newProjectName = args[0];
   const options = minimist(args);
 
-  generateProject(projectDir, newProjectName, options);
+  if (listTemplatesAndExit(newProjectName, options)) {
+    // Just listing templates using 'react-native init --template'
+    // Not creating a new app.
+    return;
+  } else {
+    console.log('Setting up new React Native app in ' + projectDir);
+    generateProject(projectDir, newProjectName, options);
+  }
 }
 
 /**
@@ -67,11 +77,7 @@ function generateProject(destinationRoot, newProjectName, options) {
     yarn.getYarnVersionIfAvailable() &&
     yarn.isGlobalCliUsingYarn(destinationRoot);
 
-  copyProjectTemplateAndReplace(
-    path.resolve('node_modules', 'react-native', 'local-cli', 'templates', 'HelloWorld'),
-    destinationRoot,
-    newProjectName
-  );
+  createProjectFromTemplate(destinationRoot, newProjectName, options.template, yarnVersion);
 
   if (yarnVersion) {
     console.log('Adding React...');

local-cli/runAndroid/runAndroid.js

@@ -193,7 +193,7 @@ function runOnAllDevices(args, cmd, packageName, adbPath){
     }
 
     console.log(chalk.bold(
-      `Building and installing the app on the device (cd android && ${cmd} ${gradleArgs.join(' ')}...`
+      `Building and installing the app on the device (cd android && ${cmd} ${gradleArgs.join(' ')})...`
     ));
 
     child_process.execFileSync(cmd, gradleArgs, {

local-cli/templates/HelloNavigation/dependencies.json

@@ -0,0 +1,3 @@
+{
+  "react-navigation": "1.0.0-beta.1"
+}

local-cli/templates/HelloNavigation/index.android.js

@@ -2,4 +2,4 @@ import { AppRegistry } from 'react-native';
 
 import MainNavigator from './views/MainNavigator';
 
-AppRegistry.registerComponent('ChatExample', () => MainNavigator);
+AppRegistry.registerComponent('HelloWorld', () => MainNavigator);

local-cli/templates/HelloNavigation/index.ios.js

@@ -2,4 +2,4 @@ import { AppRegistry } from 'react-native';
 
 import MainNavigator from './views/MainNavigator';
 
-AppRegistry.registerComponent('ChatExample', () => MainNavigator);
+AppRegistry.registerComponent('HelloWorld', () => MainNavigator);

local-cli/templates/HelloNavigation/views/HomeScreenTabNavigator.js

@@ -7,18 +7,18 @@ import {
 import { TabNavigator } from 'react-navigation';
 
 import ChatListScreen from './chat/ChatListScreen';
-import FriendListScreen from './friends/FriendListScreen';
+import WelcomeScreen from './welcome/WelcomeScreen';
 
 /**
  * Screen with tabs shown on app startup.
  */
 const HomeScreenTabNavigator = TabNavigator({
+  Welcome: {
+    screen: WelcomeScreen,
+  },
   Chats: {
     screen: ChatListScreen,
   },
-  Friends: {
-    screen: FriendListScreen,
-  },
 });
 
 export default HomeScreenTabNavigator;

local-cli/templates/HelloNavigation/views/chat/ChatListScreen.js

@@ -10,7 +10,7 @@ import ListItem from '../../components/ListItem';
 export default class ChatListScreen extends Component {
 
   static navigationOptions = {
-    title: 'Chats',
+    title: 'Friends',
     header: {
       visible: Platform.OS === 'ios',
     },

local-cli/templates/HelloNavigation/views/friends/FriendListScreen.js → local-cli/templates/HelloNavigation/views/welcome/WelcomeScreen.js

@@ -8,19 +8,20 @@ import {
 } from 'react-native';
 
 import ListItem from '../../components/ListItem';
+import WelcomeText from './WelcomeText';
 
-export default class FriendListScreen extends Component {
+export default class WelcomeScreen extends Component {
 
   static navigationOptions = {
-    title: 'Friends',
+    title: 'Welcome',
     header: {
       visible: Platform.OS === 'ios',
     },
     tabBar: {
       icon: ({ tintColor }) => (
         <Image
           // Using react-native-vector-icons works here too
-          source={require('./friend-icon.png')}
+          source={require('./welcome-icon.png')}
           style={[styles.icon, {tintColor: tintColor}]}
         />
       ),
@@ -29,9 +30,7 @@ export default class FriendListScreen extends Component {
 
   render() {
     return (
-      <View style={styles.container}>
-        <Text>A list of friends here.</Text>
-      </View>
+      <WelcomeText />
     );
   }
 }

local-cli/templates/HelloNavigation/views/welcome/WelcomeText.android.js

@@ -0,0 +1,51 @@
+import React, { Component } from 'react';
+import {
+  AppRegistry,
+  StyleSheet,
+  Text,
+  View
+} from 'react-native';
+
+export default class WelcomeText extends Component {
+  render() {
+    return (
+      <View style={styles.container}>
+        <Text style={styles.welcome}>
+          Welcome to React Native!
+        </Text>
+        <Text style={styles.instructions}>
+          This app shows the basics of navigating between a few screens,
+          working with ListView and handling text input.
+        </Text>
+        <Text style={styles.instructions}>
+          Modify any files to get started. For example try changing the
+          file views/welcome/WelcomeText.android.js.
+        </Text>
+        <Text style={styles.instructions}>
+          Press Cmd+R to reload,{'\n'}
+          Cmd+D or shake for dev menu.
+        </Text>
+      </View>
+    );
+  }
+}
+
+const styles = StyleSheet.create({
+  container: {
+    flex: 1,
+    justifyContent: 'center',
+    alignItems: 'center',
+    backgroundColor: 'white',
+    padding: 20,
+  },
+  welcome: {
+    fontSize: 20,
+    textAlign: 'center',
+    margin: 16,
+  },
+  instructions: {
+    textAlign: 'center',
+    color: '#333333',
+    marginBottom: 12,
+  },
+});

local-cli/templates/HelloNavigation/views/welcome/WelcomeText.ios.js

@@ -0,0 +1,51 @@
+import React, { Component } from 'react';
+import {
+  AppRegistry,
+  StyleSheet,
+  Text,
+  View
+} from 'react-native';
+
+export default class WelcomeText extends Component {
+  render() {
+    return (
+      <View style={styles.container}>
+        <Text style={styles.welcome}>
+          Welcome to React Native!
+        </Text>
+        <Text style={styles.instructions}>
+          This app shows the basics of navigating between a few screens,
+          working with ListView and handling text input.
+        </Text>
+        <Text style={styles.instructions}>
+          Modify any files to get started. For example try changing the
+          file{'\n'}views/welcome/WelcomeText.ios.js.
+        </Text>
+        <Text style={styles.instructions}>
+          Press Cmd+R to reload,{'\n'}
+          Cmd+D or shake for dev menu.
+        </Text>
+      </View>
+    );
+  }
+}
+
+const styles = StyleSheet.create({
+  container: {
+    flex: 1,
+    justifyContent: 'center',
+    alignItems: 'center',
+    backgroundColor: 'white',
+    padding: 20,
+  },
+  welcome: {
+    fontSize: 20,
+    textAlign: 'center',
+    margin: 16,
+  },
+  instructions: {
+    textAlign: 'center',
+    color: '#333333',
+    marginBottom: 12,
+  },
+});

react-native-cli/index.js

@@ -48,6 +48,7 @@ var semver = require('semver');
  *   if you are in a RN app folder
  * init - to create a new project and npm install it
  *   --verbose - to print logs while init
+ *   --template - name of the template to use, e.g. --template navigation
  *   --version <alternative react-native package> - override default (https://registry.npmjs.org/react-native@latest),
  *      package to install, examples:
  *     - "0.22.0-rc1" - A new app will be created using a specific version of React Native from npm repo
@@ -129,7 +130,8 @@ if (cli) {
       '  Options:',
       '',
       '    -h, --help    output usage information',
-      '    -v, --version output the version number',
+      '    -v, --version use a specific version of React Native',
+      '    --template use an app template. Use --template to see available templates.',
       '',
     ].join('\n'));
     process.exit(0);
@@ -264,8 +266,7 @@ function getInstallPackage(rnPackage) {
 }
 
 function run(root, projectName, options) {
-  // E.g. '0.38' or '/path/to/archive.tgz'
-  const rnPackage = options.version;
+  const rnPackage = options.version; // e.g. '0.38' or '/path/to/archive.tgz'
   const forceNpmClient = options.npm;
   const yarnVersion = (!forceNpmClient) && getYarnVersionIfAvailable();
   var installCommand;