从 Angular2 升级到 Angular4 后 ng build --prod 失败

Question

升级后，我的 Angular2 项目到 Angular4 使用：

npm install @angular/common@latest @angular/compiler@latest @angular/compiler-cli@latest @angular/core@latest @angular/forms@latest @angular/http@latest @angular/platform-browser@latest @angular/platform-browser-dynamic@latest @angular/platform-server@latest @angular/router@latest @angular/animations@latest typescript@latest --save

我在使用 ng build --prod 时收到以下错误：

ERROR in ./src/main.ts
Module not found: Error: Can't resolve './$$_gendir/app/app.module.ngfactory' in 'D:\workspace\MyProject\src'
 @ ./src/main.ts 4:0-74
 @ multi ./src/main.ts

没有 --prod 标志，我不会收到任何错误。在 Whosebug 上有几个类似的问题，但没有任何可接受的答案，并且与升级到 Angular4 无关。这是我的 package.json:

{
  "name": "MyProject",
  "version": "0.0.0",
  "license": "MIT",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "^4.0.0",
    "@angular/common": "^4.0.0",
    "@angular/compiler": "^4.0.0",
    "@angular/core": "^4.0.0",
    "@angular/forms": "^4.0.0",
    "@angular/http": "^4.0.0",
    "@angular/platform-browser": "^4.0.0",
    "@angular/platform-browser-dynamic": "^4.0.0",
    "@angular/platform-server": "^4.0.0",
    "@angular/router": "^4.0.0",
    "angular-2-dropdown-multiselect": "^1.0.5",
    "angular2-uuid": "^1.1.1",
    "bootstrap": "^3.3.7",
    "core-js": "^2.4.1",
    "font-awesome": "^4.7.0",
    "jquery": "^3.1.1",
    "ng2-adal": "^0.3.0",
    "rxjs": "^5.1.0",
    "zone.js": "^0.8.4"
  },
  "devDependencies": {
    "@angular/cli": "1.0.0",
    "@angular/compiler-cli": "^4.0.0",
    "@types/jasmine": "2.5.46",
    "@types/node": "~7.0.11",
    "codelyzer": "~2.0.0",
    "jasmine-core": "~2.5.2",
    "jasmine-spec-reporter": "~3.2.0",
    "karma": "~1.5.0",
    "karma-chrome-launcher": "~2.0.0",
    "karma-cli": "~1.0.1",
    "karma-coverage-istanbul-reporter": "^1.0.0",
    "karma-jasmine": "~1.1.0",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.1.0",
    "ts-node": "~2.0.0",
    "typescript": "^2.2.1",
    "tslint": "~4.5.0"
  }
}

编辑。这是使用 ng new 和新 CLI 创建的 project.json：

{
  "name": "mypro",
  "version": "0.0.0",
  "license": "MIT",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/common": "^4.0.0",
    "@angular/compiler": "^4.0.0",
    "@angular/core": "^4.0.0",
    "@angular/forms": "^4.0.0",
    "@angular/http": "^4.0.0",
    "@angular/platform-browser": "^4.0.0",
    "@angular/platform-browser-dynamic": "^4.0.0",
    "@angular/router": "^4.0.0",
    "core-js": "^2.4.1",
    "rxjs": "^5.1.0",
    "zone.js": "^0.8.4"
  },
  "devDependencies": {
    "@angular/cli": "1.0.0",
    "@angular/compiler-cli": "^4.0.0",
    "@types/jasmine": "2.5.38",
    "@types/node": "~6.0.60",
    "codelyzer": "~2.0.0",
    "jasmine-core": "~2.5.2",
    "jasmine-spec-reporter": "~3.2.0",
    "karma": "~1.4.1",
    "karma-chrome-launcher": "~2.0.0",
    "karma-cli": "~1.0.1",
    "karma-jasmine": "~1.1.0",
    "karma-jasmine-html-reporter": "^0.2.2",
    "karma-coverage-istanbul-reporter": "^0.2.0",
    "protractor": "~5.1.0",
    "ts-node": "~2.0.0",
    "tslint": "~4.5.0",
    "typescript": "~2.2.0"
  }
}

有什么建议吗？

Answer 1

您可以构建您的应用程序，但您很可能需要将 --aot false 参数与 --prod 一起包含在内才能使其正常工作。见下文。

ng build --prod --aot false

现在默认的生产构建编译模式是AOT编译。您必须在代码中执行一些额外的步骤才能让 AOT 工作，或者通过将标志设置为 false 来避免它。 AOT Cookbook 应该会有一些帮助。

ng build 的 GitHub wiki 表示 --aot 标志的默认值为 false，但事实似乎并非如此。 ng build --help 不表示有默认值。使用标志 shows/proves 默认为真。

当我运行遇到 AOT 问题时，我通常会收到比您在问题中显示的更好的错误消息；至少是一个组件名称，或者告诉我在哪里看的东西。我最终在我的错误中看到的许多内容都是诸如未在组件中显式声明变量之类的事情。 JIT 不关心这个，但 AOT 根本不喜欢它。

希望对您有所帮助。

从 Angular2 升级到 Angular4 后 ng build --prod 失败

ng build --prod fails after upgrade from Angular2 to Angular4

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