AngularJS Migration

AngularJS Migration sits at the heart of migration in single-spa. This guide walks through the concept step by step, with examples, a cheatsheet, and common mistakes to avoid.

AngularJS Migration Overview

At its core, angularjs migration 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 angularjs migration pays off across the whole codebase: fewer surprises, easier testing, and smoother onboarding. The snippet below is a solid starting point.

import { singleSpaAngular } from 'single-spa-angular';
import { enableProdMode } from '@angular/core';
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { AppModule } from './app/app.module';

export const { bootstrap, mount, unmount } = singleSpaAngular({
  bootstrapFunction: () => platformBrowserDynamic().bootstrapModule(AppModule),
  template: '<app-root />',
});

single-spa-angular wraps an Angular module as a single-spa micro frontend.

AngularJS Migration Example

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

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

Single-SPA Cheatsheet

Core single-spa APIs related to angularjs migration.

API	Example	Purpose
registerApplication	`registerApplication({ name, app, activeWhen })`	Register a micro frontend
activeWhen	`activeWhen: ['/checkout']`	Route ownership
start	`start()`	Begin routing
bootstrap	`export async function bootstrap()`	One-time setup
mount	`export async function mount(props)`	Render the app
unmount	`export async function unmount(props)`	Clean up the app
import map	`systemjs-importmap`	Locate app bundles

How AngularJS Migration Works in Single-SPA

AngularJS Migration 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.

single-spa-angular wraps an Angular module as a single-spa micro frontend.

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 AngularJS Migration

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

Concern	Recommendation
Isolation	One app's crash should not break others
Shared state	Prefer shared utility modules over globals
Routing	Keep activeWhen rules explicit and non-overlapping
Deployment	Release via import-map updates per app

Common Mistakes

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

Key Takeaways

AngularJS Migration is a core part of working effectively with single-spa.
Start small and keep angularjs migration focused on a single responsibility.
Apply consistent patterns so angularjs migration scales across your project.
Test and document angularjs migration to keep it maintainable over time.

Pro Tip

Bookmark this angularjs migration pattern and reuse it. Consistency across your single-spa codebase is worth more than clever one-off solutions.