Generic React reducer for all component lifecycles

generic-reducer.ts

export type ActionState<T> = {
  data?: T;
  isBusy: boolean;
  hasError: boolean;
  errorMessage?: string;
};

export type ActionResult<T> =
  | { type: "busy" }
  | { type: "success"; result: T }
  | { type: "error"; error: string };

export const createActionReducer = <T>() => (
    state: ActionState<T>,
    action: ActionResult<T>
  ): ActionState<T> => {
  switch (action.type) {
    case "busy":
      return { isBusy: true, hasError: false };
    case "success":
      return { isBusy: false, hasError: false, data: action.result };
    case "error":
      return { isBusy: false, hasError: true, errorMessage: action.error };
  }
};