𝗦𝘁𝗼𝗽 𝗥𝗮𝗰𝗲 𝗖𝗼𝗻𝗱𝗶𝘁𝗶𝗼𝗻𝘀 𝗪𝗶𝘁𝗵 𝗥𝗲𝗮𝗰𝘁 𝗔𝗯𝗼𝗿𝘁𝗖𝗼𝗻𝘁𝗿𝗼𝗹𝗹𝗲𝗿𝘀

Users move fast in web apps. This speed creates two main problems for developers.

The first problem is the unmounted component trap. A user clicks a button to fetch data. The request takes four seconds. After two seconds, the user clicks back and leaves the page. The request continues in the background. When the data arrives, the code tries to update a component that no longer exists. This causes memory leaks.

The second problem is the race condition. This happens often in search bars.

  • A user types "A". Request 1 starts.
  • A user types "AB". Request 2 starts.
  • Request 2 finishes first and shows correct data.
  • Request 1 finishes late and overwrites the screen with old data.

You fix both issues with the AbortController API. This tool lets you stop a network request when it is no longer needed.

How to implement it:

  • Create a new AbortController inside your useEffect.
  • Pass the controller signal to your fetch request.
  • Use a try/catch block to handle the error.
  • Check if the error name is AbortError to ignore intentional cancellations.
  • Return a cleanup function in your useEffect to call controller.abort().

This pattern works when a component unmounts or when a dependency changes.

Benefits of this approach:

  • You stop outdated data from overwriting new data.
  • You prevent memory leaks in your React app.
  • You free up browser network connections.
  • Your application stays predictable and stable.

Source: https://dev.to/iprajapatiparesh/stop-race-conditions-react-abortcontrollers-2899