# state-change

State-transition tracking primitive: pairs the previous and current state of a slice for change-driven side effects.

[`StateChange`](https://www.hyperfrontend.dev/docs/libraries/state-machine/state-change/#api-StateChange) represents the diff between two state snapshots so subscribers (UI render hooks, side-effect runners, lifecycle callbacks) can react to specific transitions rather than every dispatch. The class is consumed internally by [`LifecycleAwareComponent`](https://www.hyperfrontend.dev/docs/libraries/state-machine/lifecycle-aware-component/#api-LifecycleAwareComponent) and exposed for application code that wants to build its own transition-driven behavior on top of the store.

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Canonical page: https://www.hyperfrontend.dev/docs/libraries/state-machine/state-change/
This file: https://www.hyperfrontend.dev/docs/libraries/state-machine/state-change.md
Documentation index: https://www.hyperfrontend.dev/llms.txt