SystemJS Errors

SystemJS Errors Overview

SystemJS Errors is a building block you will reach for often in single-spa. It keeps related logic together and makes your intent obvious to reviewers and future maintainers.

When you learn systemjs errors properly, you avoid the guesswork that leads to bugs and rework. The example below shows the shape you will use in most real single-spa projects.

<script type="systemjs-importmap">
{
  "imports": {
    "@org/root-config": "//localhost:9000/org-root-config.js",
    "@org/navbar": "//localhost:8500/org-navbar.js"
  }
}
</script>

Import maps tell SystemJS where to load each micro frontend bundle at runtime.

SystemJS Errors Example

registerApplication({
  name: '@org/app',
  app: () => System.import('@org/app'),
  activeWhen: ['/app'],
});
start();

• Start from a minimal SystemJS Errors example and grow it only as needed.
• Keep configuration explicit so SystemJS Errors behaves the same in every environment.
• Name things clearly so teammates understand your SystemJS Errors at a glance.
• Add tests around SystemJS Errors early to lock in expected behaviour.

Single-SPA Cheatsheet

Core single-spa APIs related to systemjs errors.

How SystemJS Errors Works in Single-SPA

SystemJS Errors is part of how single-spa lets multiple applications — even in different frameworks — coexist on one page. A root config registers each app and controls when it is active.

Import maps tell SystemJS where to load each micro frontend bundle at runtime.

• A root config registers apps and calls start().
• Each app exports bootstrap, mount, and unmount lifecycles.
• activeWhen decides which routes each app owns.
• Import maps resolve each app's bundle at runtime.

Practical Guidance for SystemJS Errors

For reliable micro frontends, systemjs errors should isolate failures and keep shared state minimal. Let each team own its app end to end while agreeing on a few shared contracts.

Common Mistakes

• Copying systemjs errors snippets without understanding what each line does.
• Skipping error handling and edge cases when wiring up systemjs errors.
• Leaving systemjs errors untested, so regressions slip into production.
• Over-engineering systemjs errors before you actually need the extra flexibility.

Key Takeaways

• SystemJS Errors is a core part of working effectively with single-spa.
• Start small and keep systemjs errors focused on a single responsibility.
• Apply consistent patterns so systemjs errors scales across your project.
• Test and document systemjs errors to keep it maintainable over time.