Angular2教程应用程序无法加载(http部分)

Question

我很难让我的本地代码在angular 2教程link的http部分工作。在对hero.service.ts进行更改之后，它在包含内存中的DB服务后立即停止工作。实际发生的情况是，应用程序只是拒绝加载，并卡在加载屏幕上。我已经找到了关于这个问题的各种帖子，但都没有抓住我的问题。我仍然猜测这与angular-in-memory-web-api或类似的东西有关。我不知道去哪里查找更多细节，也不知道如何解决这个问题。

systemjs.config.js

/**
 * System configuration for Angular samples
 * Adjust as necessary for your application needs.
 */
(function (global) {
  System.config({
    paths: {
      // paths serve as alias
      'npm:': 'node_modules/'
    },
    // map tells the System loader where to look for things
    map: {
      // our app is within the app folder
      app: 'app',
      // angular bundles
      '@angular/core': 'npm:@angular/core/bundles/core.umd.js',
      '@angular/common': 'npm:@angular/common/bundles/common.umd.js',
      '@angular/compiler': 'npm:@angular/compiler/bundles/compiler.umd.js',
      '@angular/platform-browser': 'npm:@angular/platform-browser/bundles/platform-browser.umd.js',
      '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic.umd.js',
      '@angular/http': 'npm:@angular/http/bundles/http.umd.js',
      '@angular/router': 'npm:@angular/router/bundles/router.umd.js',
      '@angular/forms': 'npm:@angular/forms/bundles/forms.umd.js',
      // other libraries
      'rxjs':                      'npm:rxjs',
      'angular-in-memory-web-api': 'npm:angular-in-memory-web-api',
    },
    // packages tells the System loader how to load when no filename and/or no extension
    packages: {
      app: {
        main: './main.js',
        defaultExtension: 'js'
      },
      rxjs: {
        defaultExtension: 'js'
      },
      'angular-in-memory-web-api': {
        main: './index.js',
        defaultExtension: 'js'
      }
    }
  });
})(this);

package.json

{
  "name": "angular-quickstart",
  "version": "1.0.0",
  "scripts": {
    "start": "tsc && concurrently \"tsc -w\" \"lite-server\" ",
    "lite": "lite-server",
    "postinstall": "typings install",
    "tsc": "tsc",
    "tsc:w": "tsc -w",
    "typings": "typings"
  },
  "licenses": [
    {
      "type": "MIT",
      "url": "https://github.com/angular/angular.io/blob/master/LICENSE"
    }
  ],
  "dependencies": {
    "@angular/common": "~2.1.0",
    "@angular/compiler": "~2.1.0",
    "@angular/core": "~2.1.0",
    "@angular/forms": "~2.1.0",
    "@angular/http": "~2.1.0",
    "@angular/platform-browser": "~2.1.0",
    "@angular/platform-browser-dynamic": "~2.1.0",
    "@angular/router": "~3.1.0",
    "@angular/upgrade": "~2.1.0",
    "angular-in-memory-web-api": "~0.1.5",
    "bootstrap": "^3.3.7",
    "core-js": "^2.4.1",
    "reflect-metadata": "^0.1.8",
    "rxjs": "5.0.0-beta.12",
    "systemjs": "0.19.39",
    "zone.js": "^0.6.25"
  },
  "devDependencies": {
    "concurrently": "^3.0.0",
    "lite-server": "^2.2.2",
    "typescript": "^2.0.3",
    "typings":"^1.4.0"
  }
}

in-memory-data.service.ts

import { InMemoryDbService } from 'angular-in-memory-web-api';

export class InMemoryDataService implements InMemoryDbService {
  createDb() {
    let heroes = [
      {id: 11, name: 'Mr. Nice'},
      {id: 12, name: 'Narco'},
      {id: 13, name: 'Bombasto'},
      {id: 14, name: 'Celeritas'},
      {id: 15, name: 'Magneta'},
      {id: 16, name: 'RubberMan'},
      {id: 17, name: 'Dynama'},
      {id: 18, name: 'Dr IQ'},
      {id: 19, name: 'Magma'},
      {id: 20, name: 'Tornado'}
    ];
    return {heroes};
  }
}

浏览器控制台显示：

08:16:31.929 Error: (SystemJS) XHR error (404 Not Found) loading http://localhost:3000/traceur
patchProperty/desc.set/wrapFn@http://localhost:3000/node_modules/zone.js/dist/zone.js:698:26
ZoneDelegate.prototype.invokeTask@http://localhost:3000/node_modules/zone.js/dist/zone.js:265:21
Zone.prototype.runTask@http://localhost:3000/node_modules/zone.js/dist/zone.js:154:28
ZoneTask/this.invoke@http://localhost:3000/node_modules/zone.js/dist/zone.js:335:28

Error loading http://localhost:3000/traceur
Unable to load transpiler to transpile http://localhost:3000/node_modules/angular-in-memory-web-api/index.js
Error loading http://localhost:3000/node_modules/angular-in-memory-web-api/index.js as "angular-in-memory-web-api" from http://localhost:3000/app/app.module.js
Stack-Trace:
(SystemJS) XHR error (404 Not Found) loading http://localhost:3000/traceur
    patchProperty/desc.set/wrapFn@http://localhost:3000/node_modules/zone.js/dist/zone.js:698:26
    ZoneDelegate.prototype.invokeTask@http://localhost:3000/node_modules/zone.js/dist/zone.js:265:21
    Zone.prototype.runTask@http://localhost:3000/node_modules/zone.js/dist/zone.js:154:28
    ZoneTask/this.invoke@http://localhost:3000/node_modules/zone.js/dist/zone.js:335:28

Error loading http://localhost:3000/traceur
Unable to load transpiler to transpile http://localhost:3000/node_modules/angular-in-memory-web-api/index.js
Error loading http://localhost:3000/node_modules/angular-in-memory-web-api/index.js as "angular-in-memory-web-api" from http://localhost:3000/app/app.module.js1localhost:3000:16:49
<anonym>localhost:3000:16
ZoneDelegate.prototype.invoke()zone.js:232
Zone.prototype.run()zone.js:114
scheduleResolveOrReject/<()zone.js:502
ZoneDelegate.prototype.invokeTask()zone.js:265
Zone.prototype.runTask()zone.js:154
drainMicroTaskQueue()zone.js:401
ZoneTask/this.invoke()zone.js:339

Answer 1

我对这个内存中的web-api有很多问题，如果不是因为这个教程，我宁愿完全避免它。我认为弹出一个简单的后端并进行真正的测试要比处理它容易得多。

我的问题是通过引用一个确切的库版本来解决的，我恐怕我不记得确切的版本是哪个了，但你可以尝试0.0.10，就像这个post中的一样。您可以在package.json中引用您需要的版本(请务必引用确切的版本，即不带"~")。

如果这不起作用，我可以尝试找出哪个版本对我有效。您还可以在控制台中检查错误，因为您可能还会遇到一些其他问题。

Answer 2

这是因为"angular-in-memory-web-api": "~0.1.5"版本中的~抓取了最新的补丁版本，当前为0.1.13。自从0.1.5以来，涉及到我们加载模块的方式已经发生了一些重大变化。

请参阅CHANGELOG

转到umd会更改您的systemjs.config和导入库的方式。

在systemjs.config.js中，您应该将映射更改为：

‘’angular in-memory-web-api‘：'npm:angular-in-memory-web-api/bundles/in-memory-web-api.umd.js’

然后从包中删除：

‘’angular in-memory-web-api‘：{ main：'./index.js'，defaultExtension：'js’}

您必须像这样导入内存中的模块(通常是在AppModule中)：

从‘angular-in-memory-web-api’导入{ InMemoryWebApiModule }；