If a developer wants to handle the error inside the component and also wants to have it bubble up, they can use this.fire('error', e) within onerror.

If anyone needs this functionality, I've made a primitive approach to forward all standard UI events, plus any others you specify: https://github.com/hperrin/svelte-material-ui/blob/273ded17c978ece3dd87f32a58dd9839e5c61325/components/forwardEvents.js

Forwarding events from the native element through the wrapper element comes with a cost, so to avoid adding extra event handlers only a few are forwarded. For all elements except <br> and <hr>, on:focus, on:blur, on:keypress, and on:click are forwarded. For audio and video, on:pause and on:play are also forwarded.