angular-modernization

Step 1: Run Angular CLI Migrations

⚠️ CRITICAL: ALWAYS use Angular CLI migrations when available. DO NOT manually migrate features that have CLI schematics.

Angular provides automated schematics that handle edge cases, update tests, and ensure correctness. Manual migration should ONLY be used for patterns not covered by CLI tools.

IMPORTANT:

• Always run the commands using npx ng.
• All the commands must be run on directories and NOT files. Use the --path option to target directories.
• Run migrations in order (some depend on others)

#### 1. Standalone Components

```bash

npx ng generate @angular/core:standalone --path= --mode=convert-to-standalone

```

NgModule-based → standalone architecture

#### 2. Control Flow Syntax

```bash

npx ng generate @angular/core:control-flow

```

ngIf, ngFor, *ngSwitch → @if, @for, @switch

#### 3. Signal Inputs

```bash

npx ng generate @angular/core:signal-input-migration

```

@Input() → signal inputs

#### 4. Signal Outputs

```bash

npx ng generate @angular/core:output-migration

```

@Output() → signal outputs

#### 5. Signal Queries

```bash

npx ng generate @angular/core:signal-queries-migration

```

@ViewChild, @ContentChild, etc. → signal queries

#### 6. inject() Function

```bash

npx ng generate @angular/core:inject-migration

```

Constructor injection → inject() function

#### 7. Self-Closing Tag

```bash

npx ng generate @angular/core:self-closing-tag

```

Updates templates to self-closing syntax

#### 8. Unused Imports

```bash

npx ng generate @angular/core:unused-imports

```

Removes unused imports

Step 2: Apply Bitwarden Patterns

See [migration-patterns.md](migration-patterns.md) for detailed examples.

1. Add OnPush change detection
2. Apply visibility modifiers (protected for template access, private for internal)
3. Convert local component state to signals
4. Keep service observables (don't convert to signals)
5. Extract business logic to services
6. Organize class members correctly
7. Update tests for standalone

Step 3: Validate

• Fix linting and formatting using npm run lint:fix
• Run tests using npm run test

If any errors occur, fix them accordingly.

Signals vs Observables

• Signals - Component-local state only (ADR-0027)
• Observables - Service state and cross-component communication (ADR-0003)
• Use toSignal() to bridge observables into signal-based components

Visibility

• protected - Template-accessible members
• private - Internal implementation

Other Rules

• Always add OnPush change detection
• No TypeScript enums (use const objects with type aliases per ADR-0025)
• No code regions (refactor instead)
• Thin components (business logic in services)

Before completing migration:

• [ ] OnPush change detection added
• [ ] Visibility modifiers applied (protected/private)
• [ ] Signals for component state, observables for service state
• [ ] Class members organized (see [migration-patterns.md](migration-patterns.md#class-member-organization))
• [ ] Tests updated and passing
• [ ] No new TypeScript enums
• [ ] No code regions

Bitwarden ADRs

• [ADR-0003: Observable Data Services](https://contributing.bitwarden.com/architecture/adr/observable-data-services)
• [ADR-0025: No TypeScript Enums](https://contributing.bitwarden.com/architecture/adr/no-enums)
• [ADR-0027: Angular Signals](https://contributing.bitwarden.com/architecture/adr/angular-signals)
• [Bitwarden Angular Style Guide](https://contributing.bitwarden.com/contributing/code-style/web/angular)

Angular Resources

• [Angular Style Guide](https://angular.dev/style-guide)
• [Angular Migrations](https://angular.dev/reference/migrations)
• [Angular CLI Schematics](https://angular.dev/tools/cli/schematics)