Why Streaming with promises in Svelte? - Purpose & Use Cases

The Big Idea

What if your app could show data instantly, without waiting for everything to load first?

The Scenario

Imagine you want to show a live feed of data updates on your webpage, like messages or stock prices, but you have to wait for the entire data to load before showing anything.

The Problem

Waiting for all data before showing anything makes the page feel slow and unresponsive. Manually updating the UI as data arrives is tricky and can cause bugs or flickering.

The Solution

Streaming with promises lets you show parts of the data as soon as they arrive, making the page feel fast and smooth without complex manual updates.

Before vs After

✗ Before

fetch('/data').then(res => res.json()).then(data => showAll(data))

✓ After

for await (const chunk of streamData()) { showPartial(chunk) }

What It Enables

It enables real-time, smooth user experiences by displaying data progressively as it streams in.

Real Life Example

Think of a chat app where messages appear instantly as they arrive, instead of waiting for the whole conversation to load.

Key Takeaways

Manual data loading delays UI updates and feels slow.

Streaming with promises shows data bit by bit as it arrives.

This creates faster, smoother, and more engaging user experiences.