Question

我正在尝试从web worker中加载aurelia框架，以便将工作者装饰为瞬态。这是工人装载机：

importScripts('/jspm_packages/system.js');
System.config({
  defaultJSExtensions: true,
  transpiler: 'none',
  paths: {
    'npm:*': '/jspm_packages/npm/*'
  },
  map: {
    'aurelia-framework': 'npm:aurelia-framework@1.0.0-rc.1.0.1',
    'aurelia-dependency-injection': 'npm:aurelia-dependency-injection@1.0.0-rc.1.0.0',
    'aurelia-binding': 'npm:aurelia-binding@1.0.0-rc.1.0.2',
    'aurelia-metadata': 'npm:aurelia-metadata@1.0.0-rc.1.0.0',
    'aurelia-templating': 'npm:aurelia-templating@1.0.0-rc.1.0.0',
    'aurelia-loader': 'npm:aurelia-loader@1.0.0-rc.1.0.0',
    'aurelia-task-queue': 'npm:aurelia-task-queue@1.0.0-rc.1.0.0',
    'aurelia-pal': 'npm:aurelia-pal@1.0.0-rc.1.0.0',
    'aurelia-path': 'npm:aurelia-path@1.0.0-rc.1.0.0',
    'aurelia-logging': 'npm:aurelia-logging@1.0.0-rc.1.0.0',
    'aurelia-polyfills': 'npm:aurelia-polyfills@1.0.0-rc.1.0.0',
    'aurelia-fetch-client': 'npm:aurelia-fetch-client@1.0.0-rc.1.0.0/aurelia-fetch-client'
  }
});
System.import('files-service')
  .then(module => {
    let fs = new module.FilesService();
  });

以下是我如何声明worker类：

@transient()
export class FilesService {
  constructor() {
    httpClient = new HttpClient();
    // rest of stuff
  }
}

我收回了这个错误：

Uncaught (in promise) Error: Reflect.defineMetadata is not a function
    at Object.define (http://localhost:9000/jspm_packages/npm/aurelia-metadata@1.0.0-rc.1.0.0/aurelia-metadata.js:49:15)
    at eval (http://localhost:9000/jspm_packages/npm/aurelia-dependency-injection@1.0.0-rc.1.0.0/aurelia-dependency-injection.js:245:33)
    at execute (http://localhost:9000/dist/files-service.js:93:67)
    at u (http://localhost:9000/jspm_packages/system.js:5:97)
    at Object.execute (http://localhost:9000/jspm_packages/system.js:5:3188)
    at y (http://localhost:9000/jspm_packages/system.js:4:9948)
    at w (http://localhost:9000/jspm_packages/system.js:4:10327)
    at p (http://localhost:9000/jspm_packages/system.js:4:8205)
    at h (http://localhost:9000/jspm_packages/system.js:4:8590)
    at http://localhost:9000/jspm_packages/system.js:4:6896
    Error loading http://localhost:9000/dist/files-service.js

知道可能出错的是什么？顺便说一句，如果工作者没有被声明为瞬态，则没有问题（在这种情况下，不需要所有这些映射）。

Answer 1

将aurelia-pal-browser包添加到您的SystemJS地图中，然后将您的代码更新为以下内容：

// Import Aurelia's [p]latform [a]bstraction [l]ibrary for the browser.
// The PAL does some basic feature detection and serves as an abstraction for
// browser globals.
System.import('aurelia-pal-browser')
  .then(pal => pal.initialize())
  // now import a small set of polyfills for things like Reflect.defineMetadata
  .then(() => System.import('aurelia-polyfills'))
  // now you should be all set...
  .then(() => System.import('files-service')
  .then(({ FilesService }) => {  // <-- look how fancy I am! ES6 destructuring FTW - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment
    let fs = new FilesService();
  });

看起来你想在你的工作人员中使用容器 - 这里是一个例子：

let container = null;

System.import('aurelia-pal-browser')
  .then(({ initialize }) => initialize())
  .then(() => System.import('aurelia-polyfills'))
  // import DI and instantiate a container for the worker to use.
  .then(() => System.import('aurelia-dependency-injection'))
  .then(({ Container }) => container = new Container())
  // use the container...
  .then(() => System.import('files-service')
  .then(({ FilesService }) => {
    let fs = container.get(FilesService);
  });

错误＆＃34; Reflect.defineMetadata＆＃34;在尝试加载瞬态Web工作者时

1 个答案: