refactor: 扩展umi generate子命令，新增RN Generator：umi g rn。

  + `umi g rn --dev`：在 NODE_ENV=development 模式下，启动watch进程，监听源码文件变动并重新生成中间代码临时文件。
  + `umi g rn`：在 NODE_ENV=production 模式下，生成中间代码临时文件。

BREAKING CHANGE: 移除子命令：`umi watch`。

Author: 徐远翔

README.md

@@ -211,14 +211,14 @@ _上文未列出的[umi 配置](https://umijs.org/config)对 **umi-preset-react-
     "android": "react-native run-android",
     "ios": "react-native run-ios",
     "start": "react-native start",
-+   "watch": "umi watch",
++   "watch": "umi g rn --dev",
     "test": "jest",
     "lint": "eslint ."
   }
 }
 ```
 
-先执行 umi watch 监听源码文件变动，重新生成临时代码：
+先启动 watch 进程监听源码文件变动，重新生成中间代码：
 
 ```npm
 yarn watch
@@ -238,10 +238,10 @@ yarn ios
 
 ### 打包
 
-先使用 umi 生成临时代码：
+先使用 umi 生成中间代码：
 
 ```npm
-umi g tmp
+umi g rn
 ```
 
 再使用[react-native bundle](https://github.com/react-native-community/cli/blob/master/docs/commands.md#bundle)构建离线包（offline bundle)。

package.json

@@ -23,8 +23,6 @@
     "@types/react-native": "^0.62.7",
     "@typescript-eslint/eslint-plugin": "^2.28.0",
     "@typescript-eslint/parser": "^2.28.0",
-    "@umijs/runtime": "^3.0.0",
-    "@umijs/types": "^3.0.0",
     "conventional-changelog": "^3.1.18",
     "cross-env": "^7.0.2",
     "eslint": "^6.8.0",
@@ -46,6 +44,7 @@
     "rimraf": "^3.0.2",
     "ts-jest": "^25.4.0",
     "typescript": "^3.8.3",
+    "umi": "^3.0.0",
     "validate-commit-msg": "^2.14.0"
   },
   "workspaces": [

packages/umi-preset-react-native/package.json

@@ -43,6 +43,7 @@
   "dependencies": {
     "@types/react-router-native": "5.1.0",
     "babel-plugin-module-resolver": "^4.0.0",
+    "memoizerific": "^1.11.3",
     "react-router-native": "5.1.2"
   }
 }

packages/umi-preset-react-native/src/index.ts

@@ -1,14 +1,11 @@
 export default function () {
   return {
     plugins: [
-      require.resolve('./plugins/commands/watch'),
+      require.resolve('./plugins/features/reactNative'),
       require.resolve('./plugins/generateFiles/react-native/exports'),
       require.resolve('./plugins/generateFiles/react-native/polyfill'),
       require.resolve('./plugins/generateFiles/react-native/runtime'),
-      require.resolve('./plugins/generateFiles/babelConfig'),
-      require.resolve('./plugins/generateFiles/metroConfig'),
-      require.resolve('./plugins/generateFiles/index'),
-      require.resolve('./plugins/features/reactNative'),
+      require.resolve('./plugins/generators/rn'),
     ],
   };
 }

packages/umi-preset-react-native/src/plugins/commands/watch.ts

@@ -7,7 +7,7 @@ import { assertExists } from '../../utils';
 export default (api: IApi) => {
   const {
     utils: { resolve, lodash, winPath },
-    paths: { absNodeModulesPath = '', absSrcPath = '', absTmpPath },
+    paths: { absNodeModulesPath = '', absSrcPath = '' },
   } = api;
 
   /**

packages/umi-preset-react-native/src/plugins/features/reactNative.ts

@@ -0,0 +1,13 @@
+export default `/**
+ * @file umi 生成临时文件
+ * @description 添加额外的babel配置，请使用以下umi配置:
+ *  + extraBabelPlugins配置：https://umijs.org/config#extrababelplugins
+ *  + extraBabelPresets配置：https://umijs.org/config#extrababelpresets
+ * @format
+ */
+module.exports = {
+  presets: {{{presets}}},
+  plugins: {{{plugins}}},
+};
+
+`;

packages/umi-preset-react-native/src/plugins/generateFiles/babelConfig.ts

@@ -0,0 +1,7 @@
+export default `/**
+ * @file umi 生成临时文件
+ * @format
+ */
+import '@@/umi';
+
+`;