下面是一个示例代码，展示了如何在Angular 8中从API端点获取数据并应用于自动完成功能。

首先，创建一个名为auto-complete.service.ts的服务文件，用于从API端点获取数据。在该文件中，添加以下代码：

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class AutoCompleteService {
  private apiUrl = 'https://api.example.com/data'; // 替换为实际的API端点URL

  constructor(private http: HttpClient) { }

  getData(): Observable {
    return this.http.get(this.apiUrl);
  }
}

接下来，在需要使用自动完成功能的组件中，例如auto-complete.component.ts，添加以下代码：

import { Component, OnInit } from '@angular/core';
import { FormControl } from '@angular/forms';
import { AutoCompleteService } from './auto-complete.service';
import { debounceTime, distinctUntilChanged, switchMap } from 'rxjs/operators';

@Component({
  selector: 'app-auto-complete',
  templateUrl: './auto-complete.component.html',
  styleUrls: ['./auto-complete.component.css']
})
export class AutoCompleteComponent implements OnInit {
  searchControl = new FormControl();
  searchResults: any[];

  constructor(private autoCompleteService: AutoCompleteService) { }

  ngOnInit() {
    this.searchControl.valueChanges
      .pipe(
        debounceTime(300),
        distinctUntilChanged(),
        switchMap(searchTerm => this.autoCompleteService.getData(searchTerm))
      )
      .subscribe(data => {
        this.searchResults = data;
      });
  }
}

在auto-complete.component.html模板中，添加以下代码：

  
{{ result }}

最后，在使用自动完成功能的模块中，例如app.module.ts，确保已导入必要的模块和服务：

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { HttpClientModule } from '@angular/common/http';

import { AppComponent } from './app.component';
import { AutoCompleteComponent } from './auto-complete/auto-complete.component';
import { AutoCompleteService } from './auto-complete/auto-complete.service';

@NgModule({
  declarations: [
    AppComponent,
    AutoCompleteComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    ReactiveFormsModule,
    HttpClientModule
  ],
  providers: [AutoCompleteService],
  bootstrap: [AppComponent]
})
export class AppModule { }

请注意，以上代码仅为示例，需要根据实际情况进行调整和修改。