使用两个共享模块的Angular 6: Component不是已知元素：

// shared-module-a.module.ts
import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { MyComponent } from './my-component/my-component.component';

@NgModule({
  declarations: [
    MyComponent
  ],
  imports: [
    CommonModule
  ],
  exports: [
    MyComponent
  ]
})
export class SharedModuleA {}

// shared-module-b.module.ts
import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { SharedModuleA } from '../shared-module-a/shared-module-a.module';

@NgModule({
  imports: [
    CommonModule,
    SharedModuleA // 导入包含MyComponent的模块
  ]
})
export class SharedModuleB {}

// app.module.ts
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { SharedModuleB } from './shared-module-b/shared-module-b.module';
import { AppComponent } from './app.component';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    SharedModuleB // 导入共享模块
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

<!-- app.component.html -->
<app-my-component></app-my-component>