Multiple event listeners per node

[LostKobrakai]

It would be quite neat to allow for multiple event listeners per node even if they're of the same type. It already works when one is using a modifier and the other doesn't, but otherwise there will be an error about Attributes need to be unique. I've already looked into the code and it could be changed by moving the check for unique attributes a few lines lower and giving it an extra case for EventHandlers. Tests are still green after the change.

<script>
  import Component from './Component.svelte';
  function onInput(event) {
    console.log(event)
  }
</script>

<Component let:listener>
  <input on:input={listener} on:input={onInput} />
</Component>

[EmilTholin]

Hi @LostKobrakai! Could you not do something like the following:

<script>
  import Component from './Component.svelte';
  function onInput(event) {
    console.log(event)
  }
</script>

<Component let:listener>
  <input on:input={e => { listener(e); onInput(e); }} />
</Component>

[LostKobrakai]

Sure, but I don't see much reason against supporting the notation I proposed especially given it already works with different modifiers. It currently seems to be more of an accidental restriction of the unique attributes check. Having the ability to attach multiple handlers is imho more in line with using multiple addEventListeners and seems easier to change, as the functions are not arbitrarily entangled.

[LostKobrakai]

This is now merged.