AI

smoothStream()

smoothStream is a utility function that creates a TransformStream for the streamText transform option to smooth out text streaming by buffering and releasing complete words with configurable delays. This creates a more natural reading experience when streaming text responses.

import { smoothStream, streamText } from 'ai';


const result = streamText({
  model,
  prompt,
  experimental_transform: smoothStream({
    delayInMs: 20, // optional: defaults to 10ms
    chunking: 'line', // optional: defaults to 'word'
  }),
});

Import 

import { smoothStream } from "ai"

API Signature

Parameters

delayInMs?:

number | null
The delay in milliseconds between outputting each chunk. Defaults to 10ms. Set to `null` to disable delays.

chunking?:

"word" | "line" | RegExp
Controls how the text is chunked for streaming. Use "word" to stream word by word (default), "line" to stream line by line, or provide a custom RegExp pattern for custom chunking.

Returns

Returns a TransformStream that:

  • Buffers incoming text chunks
  • Releases text when the chunking pattern is encountered
  • Adds configurable delays between chunks for smooth output
  • Passes through non-text chunks (like step-finish events) immediately