All modifiers

ModifierSyntaxEffect
debouncedata-on:input__debounce.300msDelays firing until N ms after the last event. Essential for search-as-you-type.
throttledata-on:scroll__throttle.100msFires at most once per N ms. Good for scroll/resize handlers.
windowdata-on:click__windowListens on window instead of the element. Use for outside-click close.
documentdata-on:keydown__documentListens on document. Slightly narrower than window.
stopdata-on:click__stopCalls event.stopPropagation(). Prevents event from bubbling.
preventdata-on:submit__preventCalls event.preventDefault(). Prevents form submit / link follow.
oncedata-on:click__onceHandler fires exactly one time, then unregisters itself.
passivedata-on:scroll__passiveAdds {passive:true} to addEventListener. Improves scroll perf.

debounce live demo

Debounced:

__stop vs no stop

Outer (clicks: )

Inner button has __stop — clicks don't propagate to outer div.

__once live demo