Action

定义方法类
默认状态变量

export class FeedZebra {
  static readonly type = '[Zoo] Feed Zebra';
  constructor(public name: string, public hayAmount: number) {}
}

state

不传参数 ```typescript export class ZooState { @Action(FeedAnimals) feedAnimals(ctx: StateContext) { const state = ctx.getState(); ctx.setState({ …state, feed: !state.feed // 不是入参改变 }); } }

this.store.dispatch(new ZooState()); // 没传参数，即feedAnimals的第二个arguments


```typescript
// naming your action metadata explicitly makes it easier to understand what the action
// is for and makes debugging easier.
export class FeedZebra {
  static readonly type = '[Zoo] FeedZebra';
  constructor(public zebraToFeed: ZebraFood) {}   // new传入的参数
}
feedZebra(ctx: StateContext<ZooStateModel>, action: FeedZebra) {// 第2个参数，对应constructor
  const state = ctx.getState();
  ctx.setState({
    ...state,
    zebraFood: [
      ...state.zebraFood,
      // this is the new ZebraFood instance that we add to the state
      action.zebraToFeed
    ]
  });
}

async

export class ZooState {
  constructor(private animalService: AnimalService) {}
  @Action(FeedAnimals)
  feedAnimals(ctx: StateContext<ZooStateModel>, action: FeedAnimals) {
    return this.animalService.feed(action.animalsToFeed).pipe(
      tap(animalsToFeedResult => {
        const state = ctx.getState();
        ctx.setState({
          ...state,
          feedAnimals: [...state.feedAnimals, animalsToFeedResult]
        });
      })
    );
  }
}

Select

相当于get

import { Select } from '@ngxs/store';
import { ZooState, ZooStateModel } from './zoo.state';
@Component({ ... })
export class ZooComponent {
  // Reads the name of the state from the state class
  @Select(ZooState) animals$: Observable<string[]>;
  // Uses the pandas memoized selector to only return pandas
  @Select(ZooState.pandas) pandas$: Observable<string[]>;
  // Also accepts a function like our select method
  @Select(state => state.zoo.animals) animals$: Observable<string[]>;
  // Reads the name of the state from the parameter
  @Select() zoo$: Observable<ZooStateModel>;
}

组件内

通过new修改变量

this.store.dispatch(new AddAnimal(name));

坑

StateContext的类型写错，导致不能setState