reactant-module/src/core/createState.ts

A module model for Reactant

import type { Reducer, Action, AnyAction } from 'redux';

/**
 * ## Description
 *
 * It allows a class state to be defined with a reducer,
 * which is often used in situations where a class state is being migrated from the Redux boilerplate code to the Reactant.
 * And it's often used in conjunction with `dispatch()`.
 *
 * ## Example
 *
 * ```ts
 * const type = 'count_increase';
 *
 * interface CountAction {
 *  type: typeof type;
 *  state: number;
 * }
 *
 * @injectable()
 * class Counter {
 *  @state
 *  count = createState<CountAction['state'], CountAction>(
 *    ($state = 0, $action) => ($action.type === type ? $action.state : $state)
 *  );
 *
 *  increase() {
 *    dispatch<CountAction>(this, {
 *      type,
 *      state: this.count + 1,
 *    });
 *  }
 * }
 *
 * const app = createApp({
 *   modules: [],
 *   main: Counter,
 *   render: () => {},
 * });
 *
 * app.instance.increase();
 * expect(app.instance.count).toBe(1);
 * ```
 */
export function createState<S = any, A extends Action = AnyAction>(
  reducer: Reducer<S, A>
): S {
  return reducer as any;
}