# JavaScript + Angular Code Review

Review {{input}} for code quality, correctness, and best practices.

## Angular Architecture
- Use `OnPush` change detection on all components that receive data via `@Input()` — it improves performance significantly
- Inject services via the constructor; avoid creating service instances manually
- Prefer smart/dumb component split: smart components fetch data; dumb components render it
- Lazy-load feature modules using `loadChildren` to keep the initial bundle small

## RxJS / Subscriptions
- Every `subscribe()` must have a corresponding unsubscribe to prevent memory leaks — use a `Subject` + `takeUntil` pattern or the `async` pipe
- Prefer the `async` pipe in templates over manual subscriptions in the component class
- Avoid nested subscriptions — use `switchMap`, `mergeMap`, or `combineLatest`
- Handle errors in observable chains with `catchError`; never let unhandled errors silently terminate a stream

## Forms
- Prefer reactive forms for complex or dynamic forms
- Validate at the form control level, not just on submit
- Sanitise user input before sending to the server

## Security
- Use Angular's built-in sanitisation; never bypass it with `bypassSecurityTrust*` without explicit justification
- No secrets or API keys in client-side code or environment files committed to source control
- Validate all data from HTTP responses before binding to the template

## Code Quality
- Add JSDoc comments on services and complex component methods
- Components should do one thing; extract logic into services or pipes
- `camelCase` for variables/functions; `PascalCase` for classes and components
- Tests with TestBed; cover template interactions and service integration

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List findings as **Critical** (security/memory leaks/crashes) -> **Major** (bugs/subscription leaks/wrong change detection) -> **Minor** (performance/style). Cite each location and suggest the concrete fix.