Hook Output Type Reference

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

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

```typescript title="Example Types"
// Streaming configuration
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: () => void
}

// Non-streaming configuration
const nonStreamingResult: HookOutput<'TestAws', { stream: false }> = {
  data: "Final response",
  finalData: "Final response",
  error: undefined,
  isError: false,
  isLoading: false,
  isSuccess: true,
  isPending: false,
  status: 'success',
  mutate: async () => "Final response",
  reset: () => void
}

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

<ParamField path="FunctionName" type="generic"

The name of the BAML function being called. Used to infer input and output types. </ParamField>

<ParamField path="Options" type="{ stream?: boolean }"

Configuration object that determines streaming behavior. Defaults to { stream?: true }. </ParamField>

Properties

<ParamField path="data" type="FinalDataType<FunctionName> | StreamDataType<FunctionName> | undefined"

The current response data. For streaming hooks, this contains either the latest streaming response or the final response. For non-streaming hooks, this only contains the final response. </ParamField>

<ParamField path="finalData" type="FinalDataType<FunctionName> | undefined"

The final response data. Only set when the request completes successfully. </ParamField>

<ParamField path="streamData" type="StreamDataType<FunctionName> | undefined"

The latest streaming response. Only available when Options['stream'] is true. </ParamField>

<ParamField path="error" type="BamlErrors | undefined"

Any error that occurred during the request. See Error Types. </ParamField>

<ParamField path="isError" type="boolean"

True if the request resulted in an error. </ParamField>

<ParamField path="isLoading" type="boolean"

True if the request is in progress (either pending or streaming). </ParamField>

<ParamField path="isPending" type="boolean"

True if the request is pending (not yet streaming or completed). </ParamField>

<ParamField path="isSuccess" type="boolean"

True if the request completed successfully. </ParamField>

<ParamField path="isStreaming" type="boolean"

True if the request is currently streaming data. Only available when Options['stream'] is true. </ParamField>

<ParamField path="status" type="HookStatus<Options>"

The current status of the request. For streaming hooks: 'idle' | 'pending' | 'streaming' | 'success' | 'error'. For non-streaming hooks: 'idle' | 'pending' | 'success' | 'error'. </ParamField>

<ParamField path="mutate" type="(...args: Parameters<ServerAction>) => Promise<OutputType>"

Function to trigger the BAML action. Returns a ReadableStream for streaming hooks, or a Promise of the final response for non-streaming hooks. </ParamField>

<ParamField path="reset" type="() => void"

Function to reset the hook state back to its initial values. </ParamField>