useStateWithHistory.md

useStateHistory

Stores defined amount of previous state values and provides handles to travel through them.

Usage

Reference

const [state, setState, stateHistory] = useStateWithHistory<S = undefined>(
  initialState?: S | (()=>S),
  capacity?: number = 10,
  initialHistory?: S
);

• state, setState and initialState are exactly the same with native React's useState hook;
• capacity - amount of history entries held by storage;
• initialHistory - if defined it will be used as initial history value, otherwise history will equal [ initialState ].
  Initial state will not be pushed to initial history.
  If entries amount is greater than capacity parameter it won't be modified on init but will be trimmed on the next call to setState;
• stateHistory - an object containing history state:
  • history: S[] - an array holding history entries. It will have the same ref all the time so be careful with that one!;
  • position: number - current position index in history;
  • capacity: number = 10 - maximum amount of history entries;
  • back: (amount?: number) => void - go back in state history, it will cause setState to be invoked and component re-render. If first element of history reached, the call will have no effect;
  • forward: (amount?: number) => void - go forward in state history, it will cause setState to be invoked and component re-render.
    If last element of history is reached, the call will have no effect;
  • go: (position: number) => void - go to arbitrary position in history.
    In case position is non-negative ot will count elements from beginning. Negative position will cause elements counting from the end, so go(-2) equals go(history.length - 1);