useSuspenseQueries.ts

'use client'
import { useQueries } from './useQueries'
import { defaultThrowOnError } from './suspense'
import type { UseSuspenseQueryOptions, UseSuspenseQueryResult } from './types'
import type {
  DefaultError,
  QueryClient,
  QueryFunction,
  SkipToken,
  ThrowOnError,
} from '@tanstack/query-core'

// Avoid TS depth-limit error in case of large array literal
type MAXIMUM_DEPTH = 20

type GetSuspenseOptions<T> =
  // Part 1: responsible for applying explicit type parameter to function arguments, if object { queryFnData: TQueryFnData, error: TError, data: TData }
  T extends {
    queryFnData: infer TQueryFnData
    error?: infer TError
    data: infer TData
  }
    ? UseSuspenseQueryOptions<TQueryFnData, TError, TData>
    : T extends { queryFnData: infer TQueryFnData; error?: infer TError }
      ? UseSuspenseQueryOptions<TQueryFnData, TError>
      : T extends { data: infer TData; error?: infer TError }
        ? UseSuspenseQueryOptions<unknown, TError, TData>
        : // Part 2: responsible for applying explicit type parameter to function arguments, if tuple [TQueryFnData, TError, TData]
          T extends [infer TQueryFnData, infer TError, infer TData]
          ? UseSuspenseQueryOptions<TQueryFnData, TError, TData>
          : T extends [infer TQueryFnData, infer TError]
            ? UseSuspenseQueryOptions<TQueryFnData, TError>
            : T extends [infer TQueryFnData]
              ? UseSuspenseQueryOptions<TQueryFnData>
              : // Part 3: responsible for inferring and enforcing type if no explicit parameter was provided
                T extends {
                    queryFn?:
                      | QueryFunction<infer TQueryFnData, infer TQueryKey>
                      | SkipToken
                    select?: (data: any) => infer TData
                    throwOnError?: ThrowOnError<any, infer TError, any, any>
                  }
                ? UseSuspenseQueryOptions<
                    TQueryFnData,
                    TError,
                    TData,
                    TQueryKey
                  >
                : T extends {
                      queryFn?:
                        | QueryFunction<infer TQueryFnData, infer TQueryKey>
                        | SkipToken
                      throwOnError?: ThrowOnError<any, infer TError, any, any>
                    }
                  ? UseSuspenseQueryOptions<
                      TQueryFnData,
                      TError,
                      TQueryFnData,
                      TQueryKey
                    >
                  : // Fallback
                    UseSuspenseQueryOptions

type GetSuspenseResults<T> =
  // Part 1: responsible for mapping explicit type parameter to function result, if object
  T extends { queryFnData: any; error?: infer TError; data: infer TData }
    ? UseSuspenseQueryResult<TData, TError>
    : T extends { queryFnData: infer TQueryFnData; error?: infer TError }
      ? UseSuspenseQueryResult<TQueryFnData, TError>
      : T extends { data: infer TData; error?: infer TError }
        ? UseSuspenseQueryResult<TData, TError>
        : // Part 2: responsible for mapping explicit type parameter to function result, if tuple
          T extends [any, infer TError, infer TData]
          ? UseSuspenseQueryResult<TData, TError>
          : T extends [infer TQueryFnData, infer TError]
            ? UseSuspenseQueryResult<TQueryFnData, TError>
            : T extends [infer TQueryFnData]
              ? UseSuspenseQueryResult<TQueryFnData>
              : // Part 3: responsible for mapping inferred type to results, if no explicit parameter was provided
                T extends {
                    queryFn?: QueryFunction<infer TQueryFnData, any> | SkipToken
                    select?: (data: any) => infer TData
                    throwOnError?: ThrowOnError<any, infer TError, any, any>
                  }
                ? UseSuspenseQueryResult<
                    unknown extends TData ? TQueryFnData : TData,
                    unknown extends TError ? DefaultError : TError
                  >
                : T extends {
                      queryFn?:
                        | QueryFunction<infer TQueryFnData, any>
                        | SkipToken
                      throwOnError?: ThrowOnError<any, infer TError, any, any>
                    }
                  ? UseSuspenseQueryResult<
                      TQueryFnData,
                      unknown extends TError ? DefaultError : TError
                    >
                  : // Fallback
                    UseSuspenseQueryResult

/**
 * SuspenseQueriesOptions reducer recursively unwraps function arguments to infer/enforce type param
 */
export type SuspenseQueriesOptions<
  T extends Array<any>,
  TResult extends Array<any> = [],
  TDepth extends ReadonlyArray<number> = [],
> = TDepth['length'] extends MAXIMUM_DEPTH
  ? Array<UseSuspenseQueryOptions>
  : T extends []
    ? []
    : T extends [infer Head]
      ? [...TResult, GetSuspenseOptions<Head>]
      : T extends [infer Head, ...infer Tail]
        ? SuspenseQueriesOptions<
            [...Tail],
            [...TResult, GetSuspenseOptions<Head>],
            [...TDepth, 1]
          >
        : Array<unknown> extends T
          ? T
          : // If T is *some* array but we couldn't assign unknown[] to it, then it must hold some known/homogenous type!
            // use this to infer the param types in the case of Array.map() argument
            T extends Array<
                UseSuspenseQueryOptions<
                  infer TQueryFnData,
                  infer TError,
                  infer TData,
                  infer TQueryKey
                >
              >
            ? Array<
                UseSuspenseQueryOptions<TQueryFnData, TError, TData, TQueryKey>
              >
            : // Fallback
              Array<UseSuspenseQueryOptions>

/**
 * SuspenseQueriesResults reducer recursively maps type param to results
 */
export type SuspenseQueriesResults<
  T extends Array<any>,
  TResult extends Array<any> = [],
  TDepth extends ReadonlyArray<number> = [],
> = TDepth['length'] extends MAXIMUM_DEPTH
  ? Array<UseSuspenseQueryResult>
  : T extends []
    ? []
    : T extends [infer Head]
      ? [...TResult, GetSuspenseResults<Head>]
      : T extends [infer Head, ...infer Tail]
        ? SuspenseQueriesResults<
            [...Tail],
            [...TResult, GetSuspenseResults<Head>],
            [...TDepth, 1]
          >
        : T extends Array<
              UseSuspenseQueryOptions<
                infer TQueryFnData,
                infer TError,
                infer TData,
                any
              >
            >
          ? // Dynamic-size (homogenous) UseQueryOptions array: map directly to array of results
            Array<
              UseSuspenseQueryResult<
                unknown extends TData ? TQueryFnData : TData,
                unknown extends TError ? DefaultError : TError
              >
            >
          : // Fallback
            Array<UseSuspenseQueryResult>

export function useSuspenseQueries<
  T extends Array<any>,
  TCombinedResult = SuspenseQueriesResults<T>,
>(
  options: {
    queries: readonly [...SuspenseQueriesOptions<T>]
    combine?: (result: SuspenseQueriesResults<T>) => TCombinedResult
  },
  queryClient?: QueryClient,
): TCombinedResult {
  return useQueries(
    {
      ...options,
      queries: options.queries.map((query) => ({
        ...query,
        suspense: true,
        throwOnError: defaultThrowOnError,
        enabled: true,
        placeholderData: undefined,
      })),
    } as any,
    queryClient,
  )
}