# Objective
Just like
[`set_if_neq`](https://docs.rs/bevy_ecs/latest/bevy_ecs/change_detection/trait.DetectChangesMut.html#method.set_if_neq),
being able to express the "I don't want to unnecessarily trigger the
change detection" but with the ability to handle the previous value if
change occurs.
## Solution
Add `replace_if_neq` to `DetectChangesMut`.
---
## Changelog
- Added `DetectChangesMut::replace_if_neq`: like `set_if_neq` change the
value only if the new value if different from the current one, but
return the previous value if the change occurs.
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