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背景獲取指示器
查詢的 status === 'pending' 狀態足以顯示查詢的初始硬載入狀態，但有時您可能希望額外顯示一個指示器，表示查詢正在背景重新獲取資料。為此，查詢還提供了一個 isFetching 布林值，您可以用來顯示它正處於獲取狀態，無論 status 變數的狀態為何：
angular-ts
@Component({
selector: 'todos',
template: `
@if (todosQuery.isPending()) {
Loading...
} @else if (todosQuery.isError()) {
An error has occurred: {{ todosQuery.error().message }}
} @else if (todosQuery.isSuccess()) {
@if (todosQuery.isFetching()) {
Refreshing...
}
@for (todos of todosQuery.data(); track todo.id) {
<todo [todo]="todo" />
}
}
`,
})
class TodosComponent {
todosQuery = injectQuery(() => ({
queryKey: ['todos'],
queryFn: fetchTodos,
}))
}
@Component({
selector: 'todos',
template: `
@if (todosQuery.isPending()) {
Loading...
} @else if (todosQuery.isError()) {
An error has occurred: {{ todosQuery.error().message }}
} @else if (todosQuery.isSuccess()) {
@if (todosQuery.isFetching()) {
Refreshing...
}
@for (todos of todosQuery.data(); track todo.id) {
<todo [todo]="todo" />
}
}
`,
})
class TodosComponent {
todosQuery = injectQuery(() => ({
queryKey: ['todos'],
queryFn: fetchTodos,
}))
}
顯示全域背景獲取載入狀態
除了個別查詢的載入狀態外，如果您希望在任何查詢正在獲取資料時（包括在背景）顯示全域載入指示器，可以使用 useIsFetching 鉤子：
angular-ts
import { injectIsFetching } from '@tanstack/angular-query-experimental'
@Component({
selector: 'global-loading-indicator',
template: `
@if (isFetching()) {
<div>Queries are fetching in the background...</div>
}
`,
})
export class GlobalLoadingIndicatorComponent {
isFetching = injectIsFetching()
}
import { injectIsFetching } from '@tanstack/angular-query-experimental'
@Component({
selector: 'global-loading-indicator',
template: `
@if (isFetching()) {
<div>Queries are fetching in the background...</div>
}
`,
})
export class GlobalLoadingIndicatorComponent {
isFetching = injectIsFetching()
}
