Enable platforms to configure CLI commands

Summary:
This change adds hooks via the `package.json` for a platform plugin to specify hooks for generating platform configurations. This change also adds hooks to allow platform plugins to participate in `link` and `unlink` commands. The goal is to move platform-specific code for platform plugins into their own repositories / node_modules.

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We need to be able to configure the CLI commands for plugin platforms (e.g., react-native-windows) in their own repositories.

(Write your test plan here. If you changed any code, please provide us with clear instructions on how you verified your changes work. Bonus points for screenshots and videos!)

- All jest tests, including new tests, pass.
- `link` and `unlink` commands are successful on iOS and Android.

(If this PR adds or changes functionality, please take some time to update the docs at https://github.com/facebook/react-native-website, and link to your PR here.)

microsoft/react-native-windows#1601

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  CATEGORY
[----------]        TYPE
[ CLI      ]   [-------------]      LOCATION
[ DOCS     ]   [ BREAKING    ]   [-------------]
[ GENERAL  ]   [ BUGFIX      ]   [-{Component}-]
[ INTERNAL ]   [ ENHANCEMENT ]   [ {File}      ]
[ IOS      ]   [ FEATURE     ]   [ {Directory} ]   |-----------|
[ ANDROID  ]   [ MINOR       ]   [ {Framework} ] - | {Message} |
[----------]   [-------------]   [-------------]   |-----------|

[CATEGORY] [TYPE] [LOCATION] - MESSAGE

 EXAMPLES:

 [IOS] [BREAKING] [FlatList] - Change a thing that breaks other things
 [ANDROID] [BUGFIX] [TextInput] - Did a thing to TextInput
 [CLI] [FEATURE] [local-cli/info/info.js] - CLI easier to do things with
 [DOCS] [BUGFIX] [GettingStarted.md] - Accidentally a thing/word
 [GENERAL] [ENHANCEMENT] [Yoga] - Added new yoga thing/position
 [INTERNAL] [FEATURE] [./scripts] - Added thing to script that nobody will see
-->

[CLI][FEATURE][local-cli/core/index.js] - Allow platform plugins to contribute to the RNConfig.
[CLI][FEATURE][local-cli/link/link.js] - Allow platform plugins to participate in the `link` command.
[CLI][FEATURE][local-cli/link/unlink.js] - Allow platform plugins to participate in the `unlink` command.
Closes #17745

Differential Revision: D6883558

Pulled By: hramos

fbshipit-source-id: ea32fe21cedd4cc02c5c0d48229f2cdb2ac8142b

Author: rozele

local-cli/core/__tests__/findPlugins.spec.js

@@ -27,33 +27,45 @@ describe('findPlugins', () => {
     jest.mock(pjsonPath, () => ({
       dependencies: {'rnpm-plugin-test': '*'},
     }));
-    expect(findPlugins([ROOT])).toHaveLength(1);
-    expect(findPlugins([ROOT])[0]).toBe('rnpm-plugin-test');
+
+    expect(findPlugins([ROOT])).toHaveProperty('commands');
+    expect(findPlugins([ROOT])).toHaveProperty('platforms');
+    expect(findPlugins([ROOT]).commands).toHaveLength(1);
+    expect(findPlugins([ROOT]).commands[0]).toBe('rnpm-plugin-test');
+    expect(findPlugins([ROOT]).platforms).toHaveLength(0);
   });
 
   it('returns an empty array if there are no plugins in this folder', () => {
     jest.mock(pjsonPath, () => ({}));
-    expect(findPlugins([ROOT])).toHaveLength(0);
+    expect(findPlugins([ROOT])).toHaveProperty('commands');
+    expect(findPlugins([ROOT])).toHaveProperty('platforms');
+    expect(findPlugins([ROOT]).commands).toHaveLength(0);
+    expect(findPlugins([ROOT]).platforms).toHaveLength(0);
   });
 
-  it('returns an empty array if there is no package.json in the supplied folder', () => {
-    expect(Array.isArray(findPlugins(['fake-path']))).toBeTruthy();
-    expect(findPlugins(['fake-path'])).toHaveLength(0);
+  it('returns an object with empty arrays if there is no package.json in the supplied folder', () => {
+    expect(findPlugins(['fake-path'])).toHaveProperty('commands');
+    expect(findPlugins(['fake-path'])).toHaveProperty('platforms');
+    expect(findPlugins(['fake-path']).commands).toHaveLength(0);
+    expect(findPlugins(['fake-path']).platforms).toHaveLength(0);
   });
 
   it('returns plugins from both dependencies and dev dependencies', () => {
     jest.mock(pjsonPath, () => ({
       dependencies: {'rnpm-plugin-test': '*'},
       devDependencies: {'rnpm-plugin-test-2': '*'},
     }));
-    expect(findPlugins([ROOT])).toHaveLength(2);
+    expect(findPlugins([ROOT])).toHaveProperty('commands');
+    expect(findPlugins([ROOT])).toHaveProperty('platforms');
+    expect(findPlugins([ROOT]).commands).toHaveLength(2);
+    expect(findPlugins([ROOT]).platforms).toHaveLength(0);
   });
 
   it('returns unique list of plugins', () => {
     jest.mock(pjsonPath, () => ({
       dependencies: {'rnpm-plugin-test': '*'},
       devDependencies: {'rnpm-plugin-test': '*'},
     }));
-    expect(findPlugins([ROOT])).toHaveLength(1);
+    expect(findPlugins([ROOT]).commands).toHaveLength(1);
   });
 });

local-cli/core/findPlugins.js

@@ -37,11 +37,19 @@ const findPluginsInReactNativePackage = (pjson) => {
   return path.join(pjson.name, pjson.rnpm.plugin);
 };
 
+const findPlatformsInPackage = (pjson) => {
+  if (!pjson.rnpm || !pjson.rnpm.platform) {
+    return [];
+  }
+
+  return path.join(pjson.name, pjson.rnpm.platform);
+};
+
 const findPluginInFolder = (folder) => {
   const pjson = readPackage(folder);
 
   if (!pjson) {
-    return [];
+    return {commands: [], platforms: []};
   }
 
   const deps = union(
@@ -51,27 +59,33 @@ const findPluginInFolder = (folder) => {
 
   return deps.reduce(
     (acc, pkg) => {
+      let commands = acc.commands;
+      let platforms = acc.platforms;
       if (isRNPMPlugin(pkg)) {
-        return acc.concat(pkg);
+        commands = commands.concat(pkg);
       }
       if (isReactNativePlugin(pkg)) {
         const pkgJson = readPackage(path.join(folder, 'node_modules', pkg));
-        if (!pkgJson) {
-          return acc;
+        if (pkgJson) {
+          commands = commands.concat(findPluginsInReactNativePackage(pkgJson));
+          platforms = platforms.concat(findPlatformsInPackage(pkgJson));
         }
-        return acc.concat(findPluginsInReactNativePackage(pkgJson));
       }
-      return acc;
+      return {commands: commands, platforms: platforms};
     },
-    []
+    {commands: [], platforms: []}
   );
 };
 
 /**
  * Find plugins in package.json of the given folder
  * @param {String} folder Path to the folder to get the package.json from
- * @type  {Array}         Array of plugins or an empty array if no package.json found
+ * @type  {Object}        Object of commands and platform plugins
  */
 module.exports = function findPlugins(folders) {
-  return uniq(flatten(folders.map(findPluginInFolder)));
+  const plugins = folders.map(findPluginInFolder);
+  return {
+    commands: uniq(flatten(plugins.map(p => p.commands))),
+    platforms: uniq(flatten(plugins.map(p => p.platforms)))
+  };
 };

local-cli/core/index.js

@@ -15,7 +15,6 @@ const Config = require('../util/Config');
 const findPlugins = require('./findPlugins');
 const findAssets = require('./findAssets');
 const ios = require('./ios');
-const windows = require('./windows');
 const wrapCommands = require('./wrapCommands');
 
 /* $FlowFixMe(>=0.54.0 site=react_native_oss) This comment suppresses an error
@@ -33,6 +32,10 @@ import type {ConfigT} from 'metro';
 
 export type RNConfig = {
   ...ConfigT,
+  /**
+   * Returns an object with all platform configurations.
+   */
+  getPlatformConfig(): Object,
   /**
    * Returns an array of project commands used by the CLI to load
    */
@@ -55,10 +58,21 @@ const attachPackage = (command, pkg) => Array.isArray(command)
   ? command.map(cmd => attachPackage(cmd, pkg))
   : { ...command, pkg };
 
+const appRoot = process.cwd();
+const plugins = findPlugins([appRoot]);
+const pluginPlatforms = plugins
+  .platforms
+  .reduce((acc, pathToPlatforms) => {
+    // $FlowFixMe non-literal require
+    return Object.assign(acc, require(path.join(appRoot, 'node_modules', pathToPlatforms)));
+  },
+  {});
+
 const defaultRNConfig = {
+
   getProjectCommands(): Array<CommandT> {
-    const appRoot = process.cwd();
-    const plugins = findPlugins([appRoot])
+    const commands = plugins
+      .commands
       .map(pathToCommands => {
         const name = pathToCommands.split(path.sep)[0];
 
@@ -70,35 +84,51 @@ const defaultRNConfig = {
         );
       });
 
-    return flatten(plugins);
+    return flatten(commands);
+  },
+
+  getPlatformConfig(): Object {
+    return {
+      ios,
+      android,
+      ...pluginPlatforms
+    };
   },
 
   getProjectConfig(): Object {
+    const platforms = this.getPlatformConfig();
     const folder = process.cwd();
     const rnpm = getRNPMConfig(folder);
 
-    return Object.assign({}, rnpm, {
-      ios: ios.projectConfig(folder, rnpm.ios || {}),
-      android: android.projectConfig(folder, rnpm.android || {}),
-      windows: windows.projectConfig(folder, rnpm.windows || {}),
+    let config = Object.assign({}, rnpm, {
       assets: findAssets(folder, rnpm.assets),
     });
+
+    Object.keys(platforms).forEach(key => {
+      config[key] = platforms[key].projectConfig(folder, rnpm[key] || {});
+    });
+
+    return config;
   },
 
   getDependencyConfig(packageName: string) {
+    const platforms = this.getPlatformConfig();
     const folder = path.join(process.cwd(), 'node_modules', packageName);
     const rnpm = getRNPMConfig(
       path.join(process.cwd(), 'node_modules', packageName)
     );
 
-    return Object.assign({}, rnpm, {
-      ios: ios.dependencyConfig(folder, rnpm.ios || {}),
-      android: android.dependencyConfig(folder, rnpm.android || {}),
-      windows: windows.dependencyConfig(folder, rnpm.windows || {}),
+    let config = Object.assign({}, rnpm, {
       assets: findAssets(folder, rnpm.assets),
       commands: wrapCommands(rnpm.commands),
       params: rnpm.params || [],
     });
+
+    Object.keys(platforms).forEach(key => {
+      config[key] = platforms[key].dependencyConfig(folder, rnpm[key] || {});
+    });
+
+    return config;
   },
 };