Support partial functions as EventHandlerFunction

[Archmonger]

Discussed in #1333

^{Originally posted by masipcat February 7, 2026}
Currently it's not possible to use a partial function as EventHandlerFunction. I could use a lambda for synchronous event handlers, but it won’t work for async event handlers.

Pseudo code of what I'm doing:

@component
def ListSelector(items):
 async def handle_select_list(item_id):
 await do_something(item_id)
 
 return [
 html.div(
 {
 "key": item["id"],
 "class": "list-select-option",
 "onclick": partial(handle_select_list, item["id"]),
 }
 )
 for item in items
 ]

I'm aware that I could refactor this code in a way that I don't need to use a partial or a lambda, but anyways, I thought it'd be better if it is supported.

It just need a couple of lines to support partial functions: masipcat@837a18c