A stale response can quietly break a recommendation tool

A recommendation page can display incorrect results even when it has performed the correct calculations. This issue occurs when two valid requests arrive in the wrong sequence. Imagine a player starting a Members search, then switching to Free-to-Play (F2P) while the initial search is still processing. The F2P request resolves quickly, and the page displays F2P methods.

Shortly after, the slower Members response arrives. If the interface accepts it, the Members-only methods replace the accurate outcome, despite the form still indicating F2P. Both the API and the screen provided valid data twice. The display became unreliable because the older answer won the race.

Assign a unique identifier to each request The OSRS Money Maker finder maintains a counter for recommendation requests. Starting a search increments the counter and stores the new value locally. A variable named `requestId` is created by incrementing `activeRecommendRequest.current`. When the response arrives, the handler verifies if the local ID matches the current counter.

If they don't align, the function returns the stored results. Changing a setting also increments the counter and discards the previous result. Any response generated before that change becomes outdated, even if the network request cannot be halted.

Player lookup requires similar safeguards The page may load public Hiscores before initiating recommendation requests. This adds another race condition. A player could type a username, initiate a lookup, then correct the name before the first lookup concludes. The same request-ID mechanism protects this scenario. Only the most recent player lookup can update the stored profile or dismiss the loading state.

The recommendation request further verifies if it remains current after waiting for Hiscores. This prevents the corrected username from being matched with the prior account's levels. The loading state can also become stale. Race protection must encompass more than the final data. An older request should not clear the spinner for a newer request or display an old error following a successful retry.

It should also avoid scrolling to results that no longer correspond to the selected settings. The current-ID check should surround every state change that depends on the request, including results, error messages, loading flags, and subsequent UI actions. The AbortController can conserve bandwidth when the API supports cancellation; nevertheless, the identity check remains vital.

Even if cancellation arrives late, a small monotonic counter ensures the interface knows which answer owns the screen. The calculation can be precise for the received request, but the product must also prove that the response still belongs to the current choices.