Modules failing to load in the System JS framework

Encountering a puzzling issue with System JS while experimenting with Angular 2.

Initially, everything runs smoothly, but at random times, System JS struggles to locate modules...

An error message pops up:

GET http://localhost:9000/angular2/platform/browser.js 404 (Not Found) @ system.src.js:4891(anonymous function) @ system.src.js:4891
GET http://localhost:9000/angular2/core.js 404 (Not Found) @ system.src.js:4891
GET http://localhost:9000/angular2/router.js 404 (Not Found) @ system.src.js:4891
GET http://localhost:9000/angular2/http.js 404 (Not Found) @ system.src.js:4891
GET http://localhost:9000/angular2/core.js 404 (Not Found) @ system.src.js:4891
GET http://localhost:9000/angular2/http.js 404 (Not Found) @ system.src.js:4891
GET http://localhost:9000/angular2/src/facade/lang.js 404 (Not Found) @ system.src.js:4891
GET http://localhost:9000/angular2/router.js 404 (Not Found) @ system.src.js:4891

The number of errors varies from time to time...

What's most bizarre is that after some waiting and repeatedly refreshing the page, the app mysteriously starts working again!

I'm using [email protected] and [email protected] (latest versions available).

The script section in index.html containing the SystemJS configuration appears like this:

<script src="./node_modules/angular2/bundles/angular2-polyfills.js"></script>
<script src="./node_modules/es6-shim/es6-shim.min.js"></script>
<script src="./node_modules/systemjs/dist/system.js"></script>
<script>
  //configure system loader
  System.config({
    defaultJSExtensions: true
  });
  //bootstrap the Angular2 application
  System.import('dist/app').catch(console.log.bind(console));
</script>
<script src="./node_modules/rxjs/bundles/Rx.js"></script>
<script src="./node_modules/angular2/bundles/angular2.dev.js"></script>
<script src="./node_modules/angular2/bundles/http.dev.js"></script>
<script src="./node_modules/angular2/bundles/router.dev.js"></script>

Has anyone else come across this problem?

Appreciate any insights or solutions. Thanks!

javascripttypescriptangularsystemjs

Answer №1

It appears that there may be an issue with your SystemJS setup:

Have you included the following script tags in your HTML entry page:

<script src="node_modules/angular2/bundles/angular2-polyfills.js"></script>
<script src="node_modules/systemjs/dist/system.src.js"></script>
<script src="node_modules/rxjs/bundles/Rx.js"></script>
<script src="node_modules/angular2/bundles/angular2.dev.js"></script>
<script src="node_modules/angular2/bundles/router.dev.js"></script>
<script src="node_modules/angular2/bundles/http.dev.js"></script>

<script>
  System.config({
    packages: {        
      app: {
        format: 'register',
        defaultExtension: 'js'
      }
    }
  });
  System.import('app/boot')
        .then(null, console.error.bind(console));
</script>

Based on the HTTP calls I observed, it seems like there might be a configuration issue in your SystemJS setup:

  System.config({
    packages: {        
      app: {
        format: 'register',
        defaultExtension: 'js'
      },
      angular2: {
        format: 'register',
        defaultExtension: 'js'
      }
    }
  });

Answer №2

It might be a stretch since I lack the necessary permissions to leave comments and request additional details. Have you attempted to verify whether the file app.ts is located within the dist/app directory?

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