Angular 5 Karma测试报错：'app-addbook'不是已知元素

Got it, let's organize your Angular book component setup clearly with proper formatting:

File Structure #

Here's the full list of files you have under /src/app/book/:

• book.component.ts
• book.module.ts
• book.component.html
• book-routing.module.ts
• addbook.component.html
• addbook.component.ts

book.component.html Code #

<button class="btn btn-outline-success" (click)="addButton()">Add Book</button>
<div *ngIf="toggleFlag">
  <app-addbook></app-addbook>
</div>

Partial book.module.ts Code #

Looks like you shared a snippet of this file, here's the formatted version:

@NgModule({
  imports: [
    CommonModule,
    ReactiveFormsModule,
    Book...

内容的提问来源于stack exchange，提问作者Niladri Banerjee - Uttarpara