Throttled Store

Utility for wrapping Svelte stores to throttle subscriber notifications, reducing update frequency for performance.

Functions

throttled(delay, store)

Creates a throttled version of a store that limits how often subscribers are notified.

Parameters:

• delay - Throttle delay in milliseconds (0 disables throttling)
• store - Any readable Svelte store

Returns: Store with throttled subscription behavior

When delay is 0, returns the original store unchanged. Otherwise, wraps the store so that subscribers receive updates at most once per delay period.

Example

import {writable} from "svelte/store"
import {throttled} from "@welshman/store"

// Create a regular store that updates frequently
const fastStore = writable(0)

// Create a throttled version that only notifies every 100ms
const slowStore = throttled(100, fastStore)

// Subscribe to both stores
fastStore.subscribe(value => console.log("Fast:", value))
slowStore.subscribe(value => console.log("Slow:", value))

// Rapidly update the store
let count = 0
const interval = setInterval(() => {
  fastStore.set(++count)

  if (count >= 10) {
    clearInterval(interval)
  }
}, 10) // Update every 10ms

// Output:
// Fast: 1, Fast: 2, Fast: 3, ... (every update)
// Slow: 1, Slow: 5, Slow: 10 (throttled to ~100ms intervals)