“{}”类型的参数不能分配给“字符串”类型的参数

Question

这是我的打字稿

export class State {
  constructor(public name: string, public population: string, public flag: string) { }
}



export class AutocompleteOverviewComponent implements OnInit {
      stateCtrl: FormControl;
      filteredStates: Observable<any[]>;
    temp:string;
      states: State[] = [
        {
          name: 'Arkansas',
          population: '2.978M',
          // https://commons.wikimedia.org/wiki/File:Flag_of_Arkansas.svg
          flag: 'https://upload.wikimedia.org/wikipedia/commons/9/9d/Flag_of_Arkansas.svg'
        },
        {
          name: 'California',
          population: '39.14M',
          // https://commons.wikimedia.org/wiki/File:Flag_of_California.svg
          flag: 'https://upload.wikimedia.org/wikipedia/commons/0/01/Flag_of_California.svg'
        },
        {
          name: 'Florida',
          population: '20.27M',
          // https://commons.wikimedia.org/wiki/File:Flag_of_Florida.svg
          flag: 'https://upload.wikimedia.org/wikipedia/commons/f/f7/Flag_of_Florida.svg'
        },
        {
          name: 'Texas',
          population: '27.47M',
          // https://commons.wikimedia.org/wiki/File:Flag_of_Texas.svg
          flag: 'https://upload.wikimedia.org/wikipedia/commons/f/f7/Flag_of_Texas.svg'
        }
      ];

      constructor() {
        this.stateCtrl = new FormControl();

      }
   ngOnInit() {
        this.filteredStates = this.stateCtrl.valueChanges
        .pipe(
          startWith(''),
          map(state => state ? this.filterStates(state) : this.states.slice(),
        )
        );
      }

      filterStates(name1:string) {
        return this.states.filter(state =>
          state.name.toLowerCase().indexOf(name1.toLowerCase()) === 0);
      }

我收到错误，例如 ** '{}' 类型的参数不可分配给 'string' 类型的参数。** 在 ngOnInit 函数上我正在调用 this.filterStates(state) 函数，但我收到错误请帮助他

Answer 1

您可以将“val”变量的类型从“string”更改为“any”，它应该可以工作。

filter(val: any): string[] { return this.options.filter(option => option.toLowerCase().includes(val.toLowerCase())); }

Answer 2

我不是 100% 确定，但可能是因为您的 filterStates 函数正在接收一个字符串：

filterStates(name1:string) {
  ...
}

但你正在传递一个对象：

map(state => state ? this.filterStates(state)