Practice Questions

How should a front-end handle streaming data from an AI model?

Q: How should a front-end handle streaming data from an AI model?

The Core Idea Streaming means you don't wait for the full response. You open a stream (SSE, WebSocket, or fetch + ReadableStream), append chunks to the UI as they arrive, and stop cleanly when the stream ends or errors.

LowIntermediateJavascript

By FrontendAtlas Team · Updated Jan 31, 2026

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Quick Answer

This checks whether you know how to implement streaming responses (SSE/WebSocket/ReadableStream), update the UI incrementally, and handle cancellation or errors cleanly.

Answer

The Core Idea

Streaming means you don't wait for the full response. You open a stream (SSE, WebSocket, or fetch + ReadableStream), append chunks to the UI as they arrive, and stop cleanly when the stream ends or errors.

Step	What happens	Why it matters
Open stream	Connect via SSE/WebSocket or fetch stream	Start receiving tokens immediately
Append chunks	Update UI incrementally as data arrives	Low latency UX
Handle errors	Show retry/state on disconnect	Resilience on flaky networks
Cancel/stop	AbortController or close socket	User can stop generation

A minimal streaming flow

JAVASCRIPT

const controller = new AbortController();
const res = await fetch('/api/stream', { signal: controller.signal });
const reader = res.body.getReader();
const decoder = new TextDecoder();
let text = '';

while (true) {
  const { done, value } = await reader.read();
  if (done) break;
  text += decoder.decode(value, { stream: true });
  render(text); // append to UI
}

// controller.abort() to cancel

Summary

Open a stream, append chunks to the UI, and handle cancel + errors gracefully. The UX should feel responsive even before the full response finishes.