AI SDK UIuseChat

useChat()

Allows you to easily create a conversational user interface for your chatbot application. It enables the streaming of chat messages from your AI provider, manages the state for chat input, and updates the UI automatically as new messages are received.

Import

React
Svelte
Vue
Solid
import { useChat } from 'ai/react'

API Signature

Parameters

api:

string = '/api/chat'
The chat completion API endpoint offered by the provider.

id:

string
An unique identifier for the chat. If not provided, a random one will be generated. When provided, the `useChat` hook with the same `id` will have shared states across components. This is useful when you have multiple components showing the same chat stream.

initialInput:

string = ''
An optional string for the initial prompt input.

initialMessages:

Messages[] = []
An optional array of initial chat messages

onToolCall:

({toolCall: ToolCall}) => void | unknown| Promise<unknown>
Optional callback function that is invoked when a tool call is received. Intended for automatic client-side tool execution. You can optionally return a result for the tool call, either synchronously or asynchronously.

onResponse:

(response: Response) => void
An optional callback that will be called with the response from the API endpoint. Useful for throwing customized errors or logging

onFinish:

(message: Message) => void
An optional callback function that is called when the completion stream ends.

onError:

(error: Error) => void
An optional callback that will be called when the chat stream encounters an error.

generateId:

() => string
Optional. A way to provide a function that is going to be used for ids for messages. If not provided generateId is used by default.

headers:

Record<string, string> | Headers
An optional object of headers to be passed to the API endpoint.

body:

any
An optional, additional body object to be passed to the API endpoint.

credentials:

'omit' | 'same-origin' | 'include'
An optional literal that sets the mode of credentials to be used on the request. Defaults to same-origin.

sendExtraMessageFields:

boolean
An optional boolean that determines whether to send extra fields you've added to `messages`.Defaults to `false` and only the `content` and `role` fields will be sent to the API endpoint.If set to `true`, the `name`, `data`, and `annotations` fields will also be sent.

maxToolRoundtrips:

number
React and SolidJS only. Maximal number of automatic roundtrips for tool calls. An automatic tool call roundtrip is a call to the server with the tool call results when all tool calls in the last assistant message have results. A maximum number is required to prevent infinite loops in the case of misconfigured tools. By default, it is set to 0, which will disable the feature.

streamMode:

'text' | 'stream-data'
An optional literal that sets the mode of the stream to be used. Defaults to `stream-data`. If set to `text`, the stream will be treated as a text stream.

fetch:

FetchFunction
Optional. A custom fetch function to be used for the API call. Defaults to the global fetch function.

experimental_prepareRequestBody:

(options: { messages: Message[]; requestData?: JSONValue; requestBody?: object }) => JSONValue
Experimental (React only). When a function is provided, it will be used to prepare the request body for the chat API. This can be useful for customizing the request body based on the messages and data in the chat.

Returns

messages:

Message[]
The current array of chat messages.

error:

Error | undefined
An error object returned by SWR, if any.

append:

(message: Message | CreateMessage, options?: ChatRequestOptions) => Promise<string | undefined>
Function to append a message to the chat, triggering an API call for the AI response. It returns a promise that resolves to full response message content when the API call is successfully finished, or throws an error when the API call fails.
ChatRequestOptions

headers:

Record<string, string> | Headers
Additional headers that should be to be passed to the API endpoint.

body:

object
Additional body JSON properties that should be sent to the API endpoint.

data:

JSONValue
Additional data to be sent to the API endpoint.

reload:

() => Promise<string | undefined>
Function to reload the last AI chat response for the given chat history. If the last message isn't from the assistant, it will request the API to generate a new response.

stop:

() => void
Function to abort the current API request.

setMessages:

(messages: Message[]) => void
Function to update the `messages` state locally without triggering an API call.

input:

string
The current value of the input field.

setInput:

React.Dispatch<React.SetStateAction<string>>
Function to update the `input` value.

handleInputChange:

(event: any) => void
Handler for the `onChange` event of the input field to control the input's value.

handleSubmit:

(event?: { preventDefault?: () => void }, options?: ChatRequestOptions) => void
Form submission handler that automatically resets the input field and appends a user message. You can use the `options` parameter to send additional data, headers and more to the server.
ChatRequestOptions

headers:

Record<string, string> | Headers
Additional headers that should be to be passed to the API endpoint.

body:

object
Additional body JSON properties that should be sent to the API endpoint.

data:

JSONValue
Additional data to be sent to the API endpoint.

isLoading:

boolean
Boolean flag indicating whether a request is currently in progress.

data:

JSONValue[]
Data returned from StreamData

addToolResult:

({toolCallId: string; result: any;}) => void
React and SolidJS only. Function to add a tool result to the chat. This will update the chat messages with the tool result and call the API route if all tool results for the last message are available.

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