Persist Components to Avoid Unmount/Remount Cycles with a persist Prop on <Route>

[bono95zg]

Description

I would like to request a new feature that prevents the unmounting and remounting of components when navigating between routes in React Router. This could be implemented by adding a persist prop to the component, allowing developers to keep certain components mounted in memory to avoid expensive re-rendering.

Problem Statement

In the current behavior of react-router, when navigating away from a route and then returning to it, the component associated with that route is unmounted and re-rendered. While this default behavior is useful in many scenarios, it can lead to performance issues for components that are expensive to render.

Some components might involve complex DOM structures, intensive calculations, or API requests that occur during initial rendering, causing significant delays when navigating back and forth. The ability to prevent remounting and avoid these performance hits would be highly beneficial.

Proposed Solution

Introduce a new prop, persist, which can be passed to the component. When present, this prop will prevent the component from unmounting when the user navigates away from the route. Instead, the component will remain in memory, allowing it to skip the re-rendering process when the user returns to the route.

Example usage:

<Route path="documents" element={<Documents />} persist />

In this case, will stay mounted when navigating away from and back to the "documents" route, avoiding expensive re-renders.

Use Cases

• Expensive-to-Render Components: Components that involve heavy rendering logic, complex DOM structures, or costly calculations will benefit from not being unmounted and re-rendered every time the user navigates away.

• Performance-Intensive UIs: In applications with complex, performance-sensitive user interfaces (such as data-heavy dashboards), it is important to reduce the performance hit of unmounting and remounting components.

• Multi-Step Processes or Wizards: When navigating between steps in a multi-step process, it’s common to switch between different routes. Keeping the components for each step mounted would help avoid costly re-renders as the user progresses back and forth through the steps.

Potential API Design Considerations

• Default Behavior: To ensure backward compatibility, components should continue to unmount and remount as usual unless the persist prop is explicitly set.

Alternatives Considered

React’s memo or useMemo: While memo or useMemo can help optimize component rendering, these solutions do not prevent unmounting or remounting. The component will still be torn down and rebuilt each time the route changes, which won’t solve the issue of avoiding expensive re-initializations.

Conclusion

The addition of a persist prop on would allow developers to control component lifecycle more efficiently, particularly in cases where the performance impact of unmounting and remounting is significant. This feature would provide an easy, declarative way to optimize route-based applications, improving performance without requiring complex workarounds.

Thank you for considering this feature request. I’m looking forward to hearing your thoughts and discussing potential implementations.