ngrx - 在 Angular 中使用 ngrx 进行状态管理时控制台记录状态数据

Question

任何人都可以建议在角度应用程序中使用 ngrx 进行状态管理时如何控制台记录状态。我已经浏览了 ngrx-store-logger，但是文档并不清楚如何创建元 reducer 和使用这个库。

Answer 1

这可以通过 meta reducer 来完成，如 NgRx example app 所示。

export function logger(reducer: ActionReducer<State>): ActionReducer<State> {
  return (state: State, action: any): any => {
    const result = reducer(state, action);
    console.groupCollapsed(action.type);
    console.log('prev state', state);
    console.log('action', action);
    console.log('next state', result);
    console.groupEnd();

    return result;
  };
}

/**
 * By default, @ngrx/store uses combineReducers with the reducer map to compose
 * the root meta-reducer. To add more meta-reducers, provide an array of meta-reducers
 * that will be composed to form the root meta-reducer.
 */
export const metaReducers: MetaReducer<State>[] = !environment.production
  ? [logger, storeFreeze]
  : [];