upstream-tanstack-query/docs/framework/lit/reference/functions/createQueryController.md

id, title

id	title
createQueryController	createQueryController

function createQueryController<TQueryFnData, TError, TData, TQueryData, TQueryKey>(
   host,
   options,
queryClient?): QueryResultAccessor<TData, TError>;

Defined in: packages/lit-query/src/createQueryController.ts:355

Creates a Lit reactive controller that subscribes the host to a single query.

The returned accessor is callable and also exposes current, refetch, suspense, and destroy. When options is a function, it is re-read during host updates so query keys and options can follow reactive host state.

If queryClient is omitted, the controller resolves the client from the nearest connected QueryClientProvider.

Type Parameters

TQueryFnData

TQueryFnData = unknown

TError

TError = Error

TData

TData = TQueryFnData

TQueryData

TQueryData = TQueryFnData

TQueryKey

TQueryKey extends readonly unknown[] = readonly unknown[]

Parameters

host

ReactiveControllerHost

The Lit reactive controller host that owns the query subscription.

options

Accessor<CreateQueryOptions<TQueryFnData, TError, TData, TQueryData, TQueryKey>>

Query observer options, or a getter that returns options.

queryClient?

QueryClient

Optional explicit query client. Provide this for controllers that should not resolve a client from Lit context.

Returns

QueryResultAccessor<TData, TError>

An accessor for the latest query result with query helper methods.

Example

import { LitElement, html } from 'lit'
import { createQueryController } from '@tanstack/lit-query'

class TodosView extends LitElement {
  private readonly todos = createQueryController(this, {
    queryKey: ['todos'],
    queryFn: async () => fetch('/api/todos').then((r) => r.json()),
  })

  render() {
    const query = this.todos()

    if (query.isPending) return html`Loading...`
    if (query.isError) return html`Error`

    return html`<ul>${query.data.map((todo) => html`<li>${todo.title}</li>`)}</ul>`
  }
}