输入'{可见性：字符串； 'line-join'：字符串; 'line-cap'：字符串; } | {能见度：字符串； }'不可分配给type

如何解决输入'{可见性：字符串； 'line-join'：字符串; 'line-cap'：字符串; } | {能见度：字符串； }'不可分配给type

我正在使用带有角的mapbox。然后，我尝试使用mapbox显示/隐藏一些内容。

所以我有这个组件：

export class ToggleLayersComponent implements OnInit {
  layouts = {
    contours: {
      visibility: 'visible','line-join': 'round','line-cap': 'round',},museums: {
      visibility: 'visible',};

  ngOnInit() {}

  toggleLayer(evt: {value: 'contours' | 'museums'}) {
    this.layouts[evt.value] = {
      ...this.layouts[evt.value],visibility: this.layouts[evt.value].visibility === 'visible' ? 'none' : 'visible',};
  }
}

但是我得到这个错误：

Type '{ visibility: string; 'line-join': string; 'line-cap': string; } | { visibility: string; }' is not assignable to type '{ visibility: string; 'line-join': string; 'line-cap': string; } & { visibility: string; }'.
  Type '{ visibility: string; }' is not assignable to type '{ visibility: string; 'line-join': string; 'line-cap': string; } & { visibility: string; }'.
    Type '{ visibility: string; }' is missing the following properties from type '{ visibility: string; 'line-join': string;

我当然先用Google搜索。但是我找不到任何解决方案。

那该如何解决呢？

谢谢

所以错误在这一行：

 this.layouts[evt.value] 

所以我什至不能再运行Angular：

ERROR in src/app/desktop-dashboard/toggle-layer/toggle-layer.component.ts:63:5 - error TS2322: Type '{ visibility: string; 'line-join': string; 'line-cap': string; } | { visibility: string; }' is not assignable to type '{ visibility: string; 'line-join': string; 'line-cap': string; } & { visibility: string; }'.    
  Type '{ visibility: string; }' is not assignable to type '{ visibility: string; 'line-join': string; 'line-cap': string; } & { visibility: string; }'.      
    Type '{ visibility: string; }' is missing the following properties from type '{ visibility: string; 'line-join': string; 'line-cap': string; }': 'line-join','line-cap'

63     this.layouts[evt.value] = {

解决方法

TypeScript编译器目前还不够“智能”。当您这样做时：

this.layouts[evt.value] = {
  ...this.layouts[evt.value]
}

它将evt.value视为类型'contours' | 'museums'，并且无法推断两次它是相同的值，两次它是相同的对象。基本上是阻止您这样做：

this.layouts['contours'] = {
  ...this.layouts['museums']
}

在您的示例中，您可以执行以下操作

this.layouts[evt.value].visibility = this.layouts[evt.value].visibility === 'visible'
  ? 'none'
  : 'visible';

但是我想您不想这样做，因为更改检测可能看不到对象引用已更改。如果这对您来说是个问题，那么除了欺骗编译器之外，我别无选择：

toggleLayer(evt: {value: 'contours' | 'museums'}) {
  const key = evt.value as 'contours';

  this.layouts[key] = {
    ...this.layouts[key],visibility: this.layouts[key].visibility === 'visible' ? 'none' : 'visible'
  };
}