如何在Angular中包含外部JS文件，以及如何在Angular中调用它？

declare var externalScript: any;

@Component({
  selector: 'app-example',
  templateUrl: './example.component.html',
  styleUrls: ['./example.component.css']
})
export class ExampleComponent implements OnInit {

  ngOnInit() {
    this.loadExternalScript();
  }

  loadExternalScript() {
    const script = document.createElement('script');
    script.src = 'assets/externalScript.js'; // 外部JS文件的路径
    script.type = 'text/javascript';
    script.async = true;
    script.onload = () => {
      this.callExternalScriptFunction();
    };
    document.head.appendChild(script);
  }

  callExternalScriptFunction() {
    externalScript.someFunction(); // 调用外部JS文件中的函数
  }

}

var externalScript = {
  someFunction: function() {
    // 执行一些操作
  }
};