我对此代码有一点问题:
import { Injectable } from '@angular/core';
import { BehaviorSubject, Subject, merge } from 'rxjs';
import { scan, map } from 'rxjs/operators';
import { boatsList } from 'src/app/shared/mocks/boats.mock';
import { CatamaranModel } from 'src/app/shared/models/catamaran.model';
import { SailBoatModel } from 'src/app/shared/models/sail-boat.model';
@Injectable({
providedIn: 'root'
})
export class BoatListService {
private boatListInitSubject: BehaviorSubject<(CatamaranModel|SailBoatModel)[]> = new BehaviorSubject(boatsList);
boatListInit$ = this.boatListInitSubject.asObservable();
private addedBoatSubject: Subject<(CatamaranModel|SailBoatModel)> = new Subject();
addedBoat$ = this.addedBoatSubject.asObservable();
boatList$ = merge(
this.boatListInit$,
this.addedBoat$
)
.pipe(
scan((acc: (CatamaranModel|SailBoatModel)[], value: CatamaranModel|SailBoatModel) => [...acc, value])
);
constructor() {
}
addBoat(boat: CatamaranModel | SailBoatModel){
this.addedBoatSubject.next(boat);
}
}
问题出在我的合并中
boatList$ = merge(
this.boatListInit$,
this.addedBoat$
)
.pipe(
scan((acc: (CatamaranModel|SailBoatModel)[], value: CatamaranModel|SailBoatModel) => [...acc, value])
);
我使用此合并为收藏夹添加了一个新对象,但addedBoat $中的对象从未添加到列表中,我也不知道为什么。 当我做地图而不是扫描时,我找不到this.addedBoat $的结果。
如果我订阅this.addedBoat $并启动addBoat函数,那么我有一个不错的对象。
我是否滥用合并?
答案 0 :(得分:0)
尝试更改此行
私人添加的BoatSubject:主题<(CatamaranModel | SailBoatModel)> =新的Subject();
到
私人添加的BoatSubject:BehaviourSubject <(CatamaranModel | SailBoatModel)> = new BehaviourSubject(您的期望值);
答案 1 :(得分:-1)
在这种情况下,您应该使用CombineLatest .....相应地更改您的通话:
import { combineLatest} from 'rxjs';
boatList$ = combineLatest(
this.boatListInit$,
this.addedBoat$
)
.pipe(
scan((acc: (CatamaranModel|SailBoatModel)[], value: CatamaranModel|SailBoatModel) => [...acc, value])
);