关于Angular directive使用的语法问题

import {
  AfterViewInit,
  Component,
  Directive,
  Input,
  OnInit
} from "@angular/core";
@Directive({
  selector: "[cxFocus]"
})
export class FocusDirective implements OnInit, AfterViewInit {
  @Input("cxFocus") public config: string;
  @Input() set cxRefreshFocusOn(_switchCondition: string) {
    console.log("Jerry new value: " + _switchCondition);
  }
  constructor() {
    console.log("Jerry directive constructor");
  }
  ngAfterViewInit(): void {
    console.log("Jerry directive in ngOnInit: " + this.config);
  }
  ngOnInit(): void {
    console.log("Jerry directive in ngOnInit: " + this.config);
  }
}
@Component({
  selector: "app-root",
  template: `
    <div [cxFocus]="jerry">Hello</div>
    <div cxFocus="Jerry config">World</div>
  `,
  styleUrls: ["./app.component.css"]
})
export class AppComponent {
  jerry = "Jerry Hello";
}