需求:在Hero列表里增添创建hero的UI,点击Add按钮之后,可以创建新的
实现步骤:
(1) 在hero Component上绘制用于新建hero的UI:
<div>
<label>Hero name:
<input #heroName />
</label>
<!-- (click) passes input value to add() and then clears the input -->
<button (click)="add(heroName.value); heroName.value=''">
add
</button>
</div>
add函数的实现:
add(name: string): void {
name = name.trim();
if (!name) { return; }
this.heroService.addHero({ name } as Hero)
.subscribe(hero => {
this.heroes.push(hero);
});
}
(2) 实现Hero Service的addHero函数:
addHero(hero: Hero): Observable<Hero> {
return this.http.post<Hero>(this.heroesUrl, hero, this.httpOptions).pipe(
tap((newHero: Hero) => this.log(`added hero w/ id=${newHero.id}`)),
catchError(this.handleError<Hero>('addHero'))
);
}
: