Hook Output

The HookOutput type defines the return type for BAML React hooks.

Usage

function Component() {
  const hook = useTestAws({ stream: true });

  return (
    <div>
      {hook.error && <div>Error: {hook.error.message}</div>}
      <button onClick={() => hook.mutate("test")} disabled={hook.isLoading}>
        Submit
      </button>
    </div>
  );
}

Type Definition

type HookOutput<FunctionName, Options extends { stream?: boolean } = { stream?: true }> = {
  data?: Options['stream'] extends false
    ? FinalDataType<FunctionName>
    : FinalDataType<FunctionName> | StreamDataType<FunctionName>
  finalData?: FinalDataType<FunctionName>
  streamData?: Options['stream'] extends false ? never : StreamDataType<FunctionName>
  error?: BamlErrors
  isError: boolean
  isLoading: boolean
  isPending: boolean
  isSuccess: boolean
  isStreaming: Options['stream'] extends false ? never : boolean
  status: HookStatus<Options>
  mutate: (...args: Parameters<ServerAction>) => Options['stream'] extends false
    ? Promise<FinalDataType<FunctionName>>
    : Promise<ReadableStream<Uint8Array>>
  reset: () => void
}

type HookStatus<Options extends { stream?: boolean }> = Options['stream'] extends false
  ? 'idle' | 'pending' | 'success' | 'error'
  : 'idle' | 'pending' | 'streaming' | 'success' | 'error'

Type Parameters

Parameter	Type	Description
FunctionName	generic	BAML function name, used to infer types
Options	{ stream?: boolean }	Streaming behavior config. Defaults to { stream?: true }

Properties

Property	Type	Description
data	FinalData | StreamData | undefined	Current response data
finalData	FinalData | undefined	Final response when complete
streamData	StreamData | undefined	Latest streaming response (streaming only)
error	BamlErrors | undefined	Error if request failed
isError	boolean	Request resulted in error
isLoading	boolean	Request in progress (pending or streaming)
isPending	boolean	Request pending (not yet streaming)
isSuccess	boolean	Request completed successfully
isStreaming	boolean	Currently streaming (streaming only)
status	HookStatus	Current request state
mutate	(...args) => Promise	Execute the BAML function
reset	() => void	Reset hook to initial state

Examples

Streaming Result

const streamingResult: HookOutput<'TestAws', { stream: true }> = {
  data: "Any response",
  finalData: "Final response",
  streamData: "Streaming response...",
  error: undefined,
  isError: false,
  isLoading: true,
  isSuccess: false,
  isStreaming: true,
  isPending: false,
  status: 'streaming',
  mutate: async () => new ReadableStream(),
  reset: () => {}
};

Non-Streaming Result

const nonStreamingResult: HookOutput<'TestAws', { stream: false }> = {
  data: "Final response",
  finalData: "Final response",
  // streamData and isStreaming not available
  error: undefined,
  isError: false,
  isLoading: false,
  isSuccess: true,
  isPending: false,
  status: 'success',
  mutate: async () => "Final response",
  reset: () => {}
};

See Also

• Generated Hooks - Hooks overview
• Hook Input - Input configuration
• Hook Data - Data type reference