查询选项

在多个地方共享 queryKey 和 queryFn，同时又能让它们彼此靠近，一个很好的方法是使用 queryOptions 助手。在运行时，这个助手只是返回你传递给它的任何东西，但在使用 TypeScript 时，它有很多优势。你可以将一个查询的所有可能选项定义在一个地方，并且你还将获得所有这些选项的类型推断和类型安全。

import { queryOptions } from '@tanstack/angular-query-experimental'

@Injectable({
  providedIn: 'root',
})
export class QueriesService {
  private http = inject(HttpClient)

  post(postId: number) {
    return queryOptions({
      queryKey: ['post', postId],
      queryFn: () => {
        return lastValueFrom(
          this.http.get<Post>(
            `https://jsonplaceholder.typicode.com/posts/${postId}`,
          ),
        )
      },
    })
  }
}

// usage:

postId = input.required({
  transform: numberAttribute,
})
queries = inject(QueriesService)

postQuery = injectQuery(() => this.queries.post(this.postId()))

queryClient.prefetchQuery(this.queries.post(23))
queryClient.setQueryData(this.queries.post(42).queryKey, newPost)

import { queryOptions } from '@tanstack/angular-query-experimental'

@Injectable({
  providedIn: 'root',
})
export class QueriesService {
  private http = inject(HttpClient)

  post(postId: number) {
    return queryOptions({
      queryKey: ['post', postId],
      queryFn: () => {
        return lastValueFrom(
          this.http.get<Post>(
            `https://jsonplaceholder.typicode.com/posts/${postId}`,
          ),
        )
      },
    })
  }
}

// usage:

postId = input.required({
  transform: numberAttribute,
})
queries = inject(QueriesService)

postQuery = injectQuery(() => this.queries.post(this.postId()))

queryClient.prefetchQuery(this.queries.post(23))
queryClient.setQueryData(this.queries.post(42).queryKey, newPost)

对于无限查询，提供了一个单独的 infiniteQueryOptions 助手。

你仍然可以在组件级别覆盖某些选项。一个非常常见且有用的模式是创建每个组件的 select 函数

// Type inference still works, so query.data will be the return type of select instead of queryFn
queries = inject(QueriesService)

query = injectQuery(() => ({
  ...groupOptions(1),
  select: (data) => data.title,
}))

// Type inference still works, so query.data will be the return type of select instead of queryFn
queries = inject(QueriesService)

query = injectQuery(() => ({
  ...groupOptions(1),
  select: (data) => data.title,
}))

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