Thinks in streams, not callbacks
RxJS is the part that separates an Angular developer from a JavaScript developer who has read the Angular documentation.
Angular, Express, MongoDB and Node. The opinionated end of the JavaScript world: more structure out of the box, a steeper start, and a codebase that tends to look the same in year three as it did in month three.
React hands you a rendering engine and asks you to decide everything else. Angular hands you the decisions. For a team that changes hands, that trade is often the right one.
RxJS is the part that separates an Angular developer from a JavaScript developer who has read the Angular documentation.
Which means testable services with clear boundaries, rather than a singleton with everything in it.
OnPush, immutable inputs and an understanding of why the application got slow when the list reached five hundred rows.
Feature modules, lazy loading, and a shared module that does not quietly become a second application.
Express API, Mongo access, and the same validation discipline the front end enforces.
Nobody on the bench knows all of this. We shortlist against what your problem actually needs, and tell you where the gaps are.
No algorithm puzzles. Every exercise below is a task this role does in a normal week, and we watch the method more than the answer.
A component that subscribes and never unsubscribes. We want to see them find it and fix it with the operator rather than a manual teardown.
Five hundred rows and a sluggish interface. The fix is change detection strategy and trackBy, and we watch whether they profile first.
An application where everything lives in one module. Restructure it, and explain what each boundary buys.
Half the state in most NgRx applications should not be there. We are listening for judgement rather than enthusiasm.
You interview every candidate we put forward, so these are yours to use. They separate somebody who has run this in production from somebody who interviews well.
Uses takeUntilDestroyed or the async pipe by default, and can explain which subscriptions complete on their own and which do not.
Manually stores subscriptions in an array. It works, it is noisy, and one missed component leaks for the life of the session.
When state is shared across distant parts of the application, or when the history of how it changed matters. Otherwise a service with a subject is smaller and clearer.
Always, because it is the Angular way. The result is three files and forty lines of boilerplate to store a boolean.
Change detection first. Asks whether components are OnPush, whether inputs are being mutated, and whether a function is being called from the template.
Starts optimising the API. Sometimes right, usually not, and it is the more expensive place to look first.
Answers in terms of team and lifespan, not features. Larger teams, longer-lived applications and higher turnover favour the framework that makes the decisions.
Argues about performance benchmarks. Both are fast enough; that was never the real difference.
It is less fashionable than React and still very widely deployed, particularly in large organisations. The signals and standalone component work of recent versions have made it considerably lighter. For a long-lived internal application it remains a defensible choice.
Usually within a couple of weeks, and it is a common request. The other direction is slower, because RxJS and dependency injection are genuinely new concepts rather than different syntax.
Yes, and the honest advice is usually a rewrite rather than an upgrade, because the two are different frameworks that share a name. We will scope both and let you choose.
Thirty minutes, and a shortlist within a day. If a mean developer is the wrong hire for what you described, you will hear that instead.
Either one reaches Umer directly. No forms sitting in a queue.