A Svelte store that acts as a clock/interval timer

Clock.svelte

<script>
  import timer from './timer.js'
  
  // create clock that updates every 500ms
  const clock = timer({interval: 500})
</script>

<!-- Expression will update every 500ms -->
Current time is: {$clock}

timer.js

import { readable } from 'svelte/store'

export default function(options={}) {
  // create a readable store with initial value set to now
  return readable(new Date(), set => {
    // the update function sets the latest date
    const update = () => set(new Date())
    		
    // setup an interval timer to update the store's value repeatedly over time
    const interval = setInterval(update, options.interval || 1000)
		
    // return unsubscribe callback:
    // it will stop the timer when the store is destroyed
    return () => clearInterval(interval)
  })
}

Thanks! Helped me understand stores a lot.

nice one.
REPL: https://svelte.dev/repl/4c0d570310854dd4b04971597720fb9f