Guides

Building Angular signals and standalone components with A...

This guide provides a structured approach to integrating Angular standalone components and signals into existing module-based applications. Focuses on architectural decisions, dependency management, and migration patterns for enterprise environments.

3-5 hours depending on application size6 steps
1

Audit existing NgModule dependencies

Identify all NgModule imports, declarations, and providers. Use ng generate module --dry-run to list module dependencies. Check for circular dependencies and shared service providers.

ng generate module --dry-run shared --flat
ng generate module --dry-run feature --flat

⚠ Common Pitfalls

  • •Missing transitive dependencies in lazy-loaded modules
  • •Shared services with module-level providers instead of root
2

Enable standalone component support

Update angular.json to include standalone: true in the build configuration. Modify main.ts to use bootstrapApplication() instead of platformBrowser().

{
  "projects": {
    "your-app": {
      "architect": {
        "build": {
          "options": {
            "standalone": true
          }
        }
      }
    }
  }
}

⚠ Common Pitfalls

  • •Forgetting to update all module entry points
  • •Incorrectly configuring BrowserModule imports
3

Convert components to standalone

Use ng generate component --standalone to create new components. For existing components, manually update metadata to remove NgModule declarations and add imports for dependencies.

import { Component } from '@angular/core';
import { CommonModule } from '@angular/common';

@Component({
  selector: 'app-example',
  template: '<p>Standalone component</p>',
  standalone: true,
  imports: [CommonModule]
})
export class ExampleComponent {}

⚠ Common Pitfalls

  • •Forgetting to add required imports for component dependencies
  • •Mixing standalone and NgModule components in the same module
4

Implement signal-based state management

Replace @Input() properties with signals using signal() and effect(). Update templates to use signal values directly. Refactor service state management to use signal-based patterns.

import { signal } from '@angular/core';

const count = signal(0);

function increment() {
  count.update(val => val + 1);
}

⚠ Common Pitfalls

  • •Not using the correct signal update syntax
  • •Forgetting to add dependencies to effect() triggers
5

Refactor module providers to root

Update service providers from NgModule providers to providedIn: 'root'. Use Angular CLI to generate services with root injection. Verify dependency resolution in component constructors.

import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root'
})
export class DataService { ... }

⚠ Common Pitfalls

  • •Legacy services with module-level providers causing multiple instances
  • •Incorrect provider configuration in lazy-loaded modules
6

Implement lazy loading for feature modules

Configure route loadChildren with function expressions. Use Angular CLI to generate lazy modules. Update app routing module to use loadChildren syntax.

const routes: Routes = [
  {
    path: 'feature',
    loadChildren: () => import('./feature/feature.module').then(m => m.FeatureModule)
  }
];

⚠ Common Pitfalls

  • •Incorrect path resolution in loadChildren
  • •Missing route configuration in parent modules

What you built

After implementing standalone components and signals, verify all dependencies through e2e tests. Monitor bundle size with Angular CLI build analytics. Maintain backward compatibility during phased migration.