Rollback Strategy

Rollback Strategy Overview

Rollback Strategy 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 rollback strategy 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.

# each micro frontend publishes its own bundle + import-map entry
@org/checkout -> https://cdn.example.com/checkout/v3/checkout.js

# update only this app's import-map entry to release it
{ "@org/checkout": "https://cdn.example.com/checkout/v3/checkout.js" }

Deploying a micro frontend is often just updating its import-map URL.

Rollback Strategy Example

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

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

Single-SPA Cheatsheet

Core single-spa APIs related to rollback strategy.

How Rollback Strategy Works in Single-SPA

Rollback Strategy 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.

Deploying a micro frontend is often just updating its import-map URL.

• 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 Rollback Strategy

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

Key Takeaways

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