angular2 rc6 quickstart，打字稿配置与rc5

Question

为什么angular2 rc6 quickstart不会从angular2 rc5 quickstart中编译文件夹node_modules？

见排除部分; angular2 rc5 quickstart，tsconfig.json：

{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "moduleResolution": "node",
    "sourceMap": true,
    "inlineSources": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "removeComments": false,
    "noImplicitAny": true
  },
  "exclude": [
    "node_modules",
    "typings/main",
    "typings/main.d.ts"
  ]
}

angular2 rc6 quickstart，no exclude section，tsconfig.json：

{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "moduleResolution": "node",
    "sourceMap": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "removeComments": false,
    "noImplicitAny": false
  }
}

当我这样做时，npm start，tsc编译所有文件包括node_modules;那没问题 ？ js文件被重写？一些节点模块是纯粹的打字稿，需要编译吗？为什么quickcript的快速入门配置与rc5和rc6不同？