angular - 类型 'Observable<unknown>' 不可分配给类型 'Observable<Lesson[]>'

Question

我正在使用 Angular 8 应用程序。我正在使用 Observable 模式形式 rxjs。但是我仍然在 Observable 行上遇到错误。

当然是用谷歌搜索错误。但是没有找到正确的answare。

所以我导入了这个:

import { Subject, Observer, Observable } from 'rxjs';

我有这一行:

    public lessonList$: Observable<Lesson[]> = this.lessonListSubject.asObservable();

但我仍然得到这个错误:

Type 'Observable<unknown>' is not assignable to type 'Observable<Lesson[]>'.
  Type '{}' is missing the following properties from type 'Lesson[]': length, pop, push, concat, and 26 more.ts(2322)

错误会消失。

谢谢

好的，这是界面类(class):

export interface Lesson {
    id: number;
    description: string;
    duration?: string;
    completed?: boolean;

}

这是整个文件:

import * as _ from 'lodash';
import { Lesson } from '../shared/model/lesson';
import { Subject, Observer, Observable } from 'rxjs';


class DataStore {

    private lessons: Lesson[] = [];

    private lessonListSubject = new Subject();

    public lessonList$: Observable<Lesson[]> = this.lessonListSubject.asObservable();



    initaliseLessonList(newList: Lesson[]) {
        this.lessons = _.clone(newList);
        this.broadCast();


    }
    addLesson(newLesson: Lesson) {

        this.lessons.push(newLesson);
        this.broadCast();
    }

    deleteLesson(deleted: Lesson) {
        _.remove(this.lessons, lesson => lesson.id === deleted.id);
        this.broadCast();


    }

    toggleView(toggled: Lesson) {
        // tslint:disable-next-line: no-shadowed-variable
        const lesson = _.find(this.lessons, lesson => lesson.id === toggled.id);

        lesson.completed = !lesson.completed;
        this.broadCast();


    }

    broadCast() {
        this.lessonListSubject.next(_.cloneDeep(this.lessons));

    }
}

export const store = new DataStore();

Answer 1

替换

private lessonListSubject = new Subject();

由

private lessonListSubject = new Subject<Lesson[]>();

这样，你就有了一个Subject<Lesson[]>而不是 Subject<unknown> .