revalidateOnFocus

revalidateOnFocus is a configuration option commonly found in data fetching libraries, particularly those designed for client-side applications such as React Query or SWR. Its purpose is to automatically trigger a re-fetch of data when the browser window or tab regains focus. This mechanism helps ensure that the data displayed to the user is as up-to-date as possible without requiring manual user intervention.

When a user switches away from a web page and then returns, or if the browser tab was in the background and becomes active again, revalidateOnFocus will initiate a data request to the server. This is beneficial because the data on the server might have changed while the user was away. By revalidating, the application can fetch the latest information and update the UI accordingly, providing a more dynamic and current user experience.

The behavior of revalidateOnFocus can often be controlled through configuration. Developers can choose to enable or disable this feature on a per-query basis or globally for the entire application. Disabling it can be useful in scenarios where frequent refetches might be detrimental, such as when dealing with data that changes very slowly or when network resources are constrained. Conversely, enabling it is generally recommended for most interactive applications where data freshness is a key aspect of usability.