Angular 2 - 404 提供商问题

Question

我在 Angular 2 应用程序中尝试添加提供商时遇到问题。我正在尝试我在网上找到的一些解决方案，但我无法弄清楚我的应用程序发生了什么。

基本上我在将提供者添加到我的代码时遇到了问题：

GET http://localhost:3000/dist/services/performances.service 404（未找到）
错误：(SystemJS) XHR 错误（404 未找到）加载 http://localhost:3000/dist/services/performances.service(…)

注意：我检查过路径没问题，可视化代码没有给我任何错误。

在下图中，您可以看到我的应用程序的输出。

应用输出

我要添加的服务：(performances.service.ts)

import {Injectable} from '@angular/core';
import {Performance} from '../common/performance';
import {PERFORMANCES} from '../data/data-performances';

@Injectable()
export class PerformancesService {
    private performances : any;

    contructor(){
        this.performances = {};
    }

    getData(){
        return this.performances = PERFORMANCES;
    }
}

我的app.component.ts

import {Component} from '@angular/core';
import {PerformancesService} from '../services/performances.service';

@Component({
  selector : 'my-app',
  template:
  `
    <header-fund-centre></header-fund-centre>
    <div class="container">
      <router-outlet></router-outlet>
    </div>
  `,
  providers: [PerformancesService]
})

export class AppComponent { }

systemjs.config.js

(function (global) {
  System.config({
    paths: {
      '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',
      // Styling
      '@ng-bootstrap/ng-bootstrap': 'node_modules/@ng-bootstrap/ng-bootstrap/bundles/ng-bootstrap.js',
    },
    // packages tells the System loader how to load when no filename and/or no extension
    packages: {
      app: {
        main: '../dist/main.js',
        defaultExtension: 'js'
      },
      rxjs: {
        defaultExtension: 'js'
      },
      'angular-in-memory-web-api': {
        main: './index.js',
        defaultExtension: 'js'
      }
    }
  });
})(this);

知道我在添加基本提供程序时遇到这个问题做错了什么吗？谢谢！

已编辑

下面你可以看到我目前使用的所有依赖项

"dependencies": {
    "@angular/common": "~2.1.1",
    "@angular/compiler": "~2.1.1",
    "@angular/core": "~2.1.1",
    "@angular/forms": "~2.1.1",
    "@angular/http": "~2.1.1",
    "@angular/platform-browser": "~2.1.1",
    "@angular/platform-browser-dynamic": "~2.1.1",
    "@angular/router": "~3.1.1",
    "@angular/upgrade": "~2.1.1",
    "@ng-bootstrap/ng-bootstrap": "^1.0.0-alpha.14",
    "angular-in-memory-web-api": "~0.1.13",
    "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": {
    "@types/core-js": "^0.9.34",
    "@types/node": "^6.0.45",
    "concurrently": "^3.0.0",
    "lite-server": "^2.2.2",
    "typescript": "^2.0.3"
  }

Answer 1

首先我在您的文件夹中看不到 .ts 文件，请确保您的 performances.service.ts 存在于 services 文件夹中。

将地图的map更改为以下

map: {
    // our app is within the app folder
    app: 'dist', //<-- changed from 'app' to 'dist
    ...
}

将您的 packages 选项更改为以下，说 dist 是包

packages: {
  dist: {
    main: 'main.js', //<-- change here, just used shorthand
    defaultExtension: 'js'
  },
  ...
}

将 PerformancesService 添加到 NgModule 的 providers 选项，以便 DI 系统在创建它的实例时识别依赖关系。

providers: [ PerformancesService ]

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