setTimeout in inputrule compositionend

1

I was adding type annotations to a slightly customized inputrules plugin when I noticed a type error from https://github.com/ProseMirror/prosemirror-inputrules/blob/master/src/inputrules.js#L69-L72

      handleDOMEvents: {
        compositionend: (view) => {
          setTimeout(() => {
            let {$cursor} = view.state.selection
            if ($cursor) run(view, $cursor.pos, $cursor.pos, "", rules, plugin)
          })
        }
      }

The documentation says that event handlers are supposed to return booleans, but in this case because it’s wrapped in a setTimeout, the return value is void.

What’s the reasoning the handler for compositionend is wrapped in a setTimeout, and is it safe to remove it?

The commit that added it is here.

Originally I thought with the delay parameter on setTimeout set to 0, it wouldn’t have any effect, but apparently it still removes the function from the execution queue.

2

Returning undefined is equivalent to returning false in this case, since the view converts the return value to a boolean before acting on it. Removing the setTimeout is definitely not a good idea here, since it’ll cause the code to dispatch a transaction before the view itself has finished handling the composition.