Dependency Management

Dependency Management Overview

At its core, dependency management is about doing one thing well inside your single-spa project. Once you understand the pattern, you can apply it consistently across features and teams.

Good dependency management pays off across the whole codebase: fewer surprises, easier testing, and smoother onboarding. The snippet below is a solid starting point.

// shared utility module exposed via the import map
export const authService = {
  getToken: () => localStorage.getItem('token'),
};

// consumed by any micro frontend
import { authService } from '@org/utils';

Shared utility modules provide cross-app services like auth without tight coupling.

Dependency Management Example

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

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

Single-SPA Cheatsheet

Core single-spa APIs related to dependency management.

How Dependency Management Works in Single-SPA

Dependency Management 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.

Shared utility modules provide cross-app services like auth without tight coupling.

• 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 Dependency Management

For reliable micro frontends, dependency management 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

• Skipping error handling and edge cases when wiring up dependency management.
• Leaving dependency management untested, so regressions slip into production.
• Over-engineering dependency management before you actually need the extra flexibility.
• Ignoring documentation, which makes dependency management hard for the next developer to change.

Key Takeaways

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