javascript - Aurelia 中的 Typescript 自动注入(inject)

Question

我是 Typescript 和 Aurelia 的新手。我正在尝试使 @autoinject 装饰器在 VS2015 ASP.NET MVC 6 项目中工作。

这是我的代码

import {autoinject} from "aurelia-framework";
import {HttpClient} from "aurelia-http-client";

@autoinject()
export class App {
       http: HttpClient;
       constructor(httpClient: HttpClient) {
          this.http = httpClient;
       }

       activate() {
          this.http.get("/api/test/")...
       }
}

当我运行它时，我收到一条错误消息，指出 this.http 未定义。

我认为我需要添加 TypeScript 的 emitDecoratorMetadata 标志，但我不知道如何添加。

我曾尝试将 tsconfig.json 文件添加到我的项目中并在编译器选项中设置该标志，但随后出现了一堆错误(重复标识符)。我该如何修复这些错误。我需要在"file"中添加一些东西吗？究竟是什么？

这是我的 config.js 文件

System.config({
  baseURL: "/",
  defaultJSExtensions: true,
  transpiler: "typescript",
  paths: {
    "npm:*": "jspm_packages/npm/*",
    "github:*": "jspm_packages/github/*"
  },

  map: {
    "aurelia-bootstrapper": "npm:aurelia-bootstrapper@1.0.0-beta.1",
    "aurelia-framework": "npm:aurelia-framework@1.0.0-beta.1.0.7",
    "aurelia-http-client": "npm:aurelia-http-client@1.0.0-beta.1",
    "typescript": "npm:typescript@1.7.5",
     ....
  }
  });

Answer 1

@autoInject() 是如何工作的？

Before you need to aware of TypeScript's emitDecoratorMetadata flag causes the TypeScript compiler to polyfill the Metadata Reflection API and add a special decorator definition to the transpiled TypeScript code.

Aurelia's @autoInject() decorator consumes the type metadata created by TypeScript's decorator and applies it to the class in the same way that the @inject(...) decorator does.

像下面这样尝试，您需要在 Type Script 的 compilerOptions 中启用新选项。

TS 配置:

{
    "version": "1.5.1",
    "compilerOptions": {
        "target": "es5",
        "module": "amd",
        "declaration": false,
        "noImplicitAny": false,
        "removeComments": false,
        "noLib": true,
        "emitDecoratorMetadata": true
    },
    "filesGlob": [
        "./**/*.ts",
        "!./node_modules/**/*.ts"
    ],
    "files": [
        // ...
    ]
}

文章片段截图:

关于 emitDecoratorMetadata 的文章:
http://blog.durandal.io/2015/05/06/getting-started-with-aurelia-and-typescript/ http://www.danyow.net/inversion-of-control-with-aurelia-part-2/

可用的类型脚本选项:
https://github.com/Microsoft/TypeScript/wiki/Compiler-Options

You can do it with Gulp-Typescript as well with Gulp option

选项:https://github.com/ivogabe/gulp-typescript#options
GitHub 问题线程:https://github.com/ivogabe/gulp-typescript/issues/100

Gulp 代码片段: gulp.task('build-ts', [], function() {

  return gulp.src(paths.typescript)
    .pipe(plumber())
    .pipe(changed(paths.output, {extension: '.js'}))
    .pipe(sourcemaps.init())
    .pipe(ts({
      declarationFiles: false,
      noExternalResolve: true,
      target: 'es5',
      module: 'commonjs',
      emitDecoratorMetadata: true,
      typescript: typescript
    }))
    .pipe(sourcemaps.write())
    .pipe(gulp.dest(paths.output));
});