GET XHR http：// localhost：3000 / traceur Angular 4

Question

我遇到以下错误：（SystemJS）XHR错误（404 Not Found）loading http://localhost:3000/traceur。 我的systemjs.config.js目前正在查看来自ngx-qrcode3的index.js，但似乎跟踪器无法转换文件。我想知道这个错误是否来自这个文件正在使用注释，如

/**
 * @param {?} canvas
 * @return {?}
 */

systemjs.config.js

(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/http/testing': 'npm:@angular/http/bundles/http-testing.umd.js',
            '@angular/router': 'npm:@angular/router/bundles/router.umd.js',
            '@angular/forms': 'npm:@angular/forms/bundles/forms.umd.js',
            'ngx-qrcode3': 'npm:ngx-qrcode3/index.js',

            // other libraries
            'rxjs': 'npm:rxjs'
        },
        // 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'
            }
        },
    });
})(this);

app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule } from '@angular/forms';
import { HttpModule } from '@angular/http';

import { AppComponent } from './app.component';
import { routing } from './app.routing';

import { NgxQRCodeModule } from 'ngx-qrcode3';
import { customHttpProvider } from './_helpers/index';
import { AlertComponent } from './_directives/index';
import { AuthGuard } from './_guards/index';
import { AlertService, AuthenticationService, UserService } from './_services/index';
import { HomeComponent } from './home/index';
import { LoginComponent } from './login/index';
import { RegisterComponent } from './register/index';

@NgModule({
    imports: [
        BrowserModule,
        FormsModule,
        HttpModule,
        routing,
        NgxQRCodeModule
    ],
    declarations: [
        AppComponent,
        AlertComponent,
        HomeComponent,
        LoginComponent,
        RegisterComponent
    ],
    providers: [
        customHttpProvider,
        AuthGuard,
        AlertService,
        AuthenticationService,
        UserService
    ],
    bootstrap: [AppComponent]
})

export class AppModule { }