Angular 4:"找不到名字'要求'

Question

我正在使用Angular 4和webpack构建一个应用程序.

我的一个组件中有以下内容:

ngOnInit() {
    require('/assets/js/regular-expresions.js');
}

当我尝试编译时,我得到:

C中的错误:/SRC/Sandbox/eat-sleep-code.com/src/app/content.component.ts(21,9):找不到名称'require'.

我已经运行npm install @types/node --save-dev并更新了我的tsconfig.json,如下所示:

{
  "compileOnSave": false,
  "compilerOptions": {
    "outDir": "./dist/out-tsc",
    "baseUrl": "src",
    "sourceMap": true,
    "declaration": false,
    "moduleResolution": "node",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "target": "es5",
    "types": [
      "node"
    ],
    "typeRoots": [
      "node_modules/@types"
    ],
    "lib": [
      "es2016",
      "dom"
    ]
  }
}

但是,唉,同样的错误不断被抛出.有任何想法吗？

---

这是我的package.json:

{
  "name": "eat-sleep-code.com",
  "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": "^4.0.1",
    "@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/material": "^2.0.0-beta.3",
    "@angular/platform-browser": "^4.0.0",
    "@angular/platform-browser-dynamic": "^4.0.0",
    "@angular/router": "^4.0.0",
    "@types/node": "^6.0.69",
    "angularfire2": "^2.0.0-beta.8",
    "core-js": "^2.4.1",
    "firebase": "^3.7.8",
    "jquery": "^3.2.1",
    "jquery-validation": "^1.16.0",
    "ng2-gist": "^1.0.0",
    "promise-polyfill": "^6.0.2",
    "requirejs": "^2.3.3",
    "rxjs": "^5.1.0",
    "typescript": "^2.2.2",
    "web-animations-js": "^2.2.4",
    "webpack": "^2.4.1",
    "zone.js": "^0.8.4"
  },
  "devDependencies": {
    "@angular/cli": "1.0.0",
    "@angular/compiler-cli": "^4.0.0",
    "@types/jasmine": "2.5.38",
    "@types/node": "^6.0.69",
    "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-coverage-istanbul-reporter": "^0.2.0",
    "karma-jasmine": "~1.1.0",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.1.0",
    "ts-node": "~2.0.0",
    "tslint": "~4.5.0",
    "typescript": "^2.2.2",
    "webpack": "^2.4.1"
  }
}

Answer 1

尝试添加declare var require: any;到顶部.

Answer 2

require()由于一些原因不建议.一,它将"打破"webpack 2和2中树抖动的有效性,它将阻止正确的代码分裂.

一个更好的选择是使用webpack的实现System.import:

System.import('/assets/js/regular-expresions.js').then(file => {
   // perform additional interactions after the resource has been asynchronously fetched
});

为了满足Typescript编译器(如您所见),您需要System通过声明它来告诉它这是一个可接受的变量:

declare var System: any;    

如果您只打算引用一次,可以将此行添加到组件中,或者可以将其添加到typings.d.ts类型定义文件中以在整个应用程序中使用它.请注意,如果更改打字文件,则需要重新启动ng serve会话.

这在构建时满足编译器,它在构建系统的运行时被劫持,将调用修补到Webpack中System.import.

反过来,Webpack将检查它是否有一个满足所请求文件的块,如果没有,它将动态创建一个脚本标签并将其插入头部,使用该async属性加载文件,这就是这个案例.

加载文件后,将对其进行解析和执行.但是,如果要通过异步.then()回调与其任何部分进行交互,则您的文件将需要导出您要调用的任何内容,例如:

export function test() {
    console.log('we called test');
}

这会将.test()函数公开给你的回调处理程序:

System.import('/assets/js/regular-expresions.js').then(file => {
   file.test();
});

Answer 3

尝试执行以下步骤来修复错误

1. npm install --save-dev @types/webpack-env

2. 在 compilerOptions 下使用以下内容更新 tsconfig.json：

   "types": [
       "webpack-env"
   ]
   

3.现在转到 tsconfig.app.json 并添加以下内容

"compilerOptions": {
 
    "types": [
      "node"
    ]
   }