feature(core/react/use-chat handleSubmit): Make event parameter optional in handleSubmit to improve robustness

[fribble186]

if e in the handleSubmit method were an optional parameter, this function would become more flexible
example:

import { useChat } from "ai/react";

const Index = () => {
  const { input, handleInputChange, handleSubmit } = useChat();
  const handleKeyDown = (e: React.KeyboardEvent<HTMLTextAreaElement>) => {
    if (e.key === "Enter") {
      e.preventDefault();
      console.log("Enter");
      handleSubmit();
    }
  };
  return (
    <div>
      <input onChange={handleInputChange} value={input} onKeyDown={handleKeyDown}/>
      <button onClick={handleSubmit}>send</button>
    </div>
  );
};
export default Index;

[lgrammel]

I like this PR. However, it needs to be changed for all ui frameworks (vue, svelte, solid) and potentially for useCompletion as well.

[fribble186]

I like this PR. However, it needs to be changed for all ui frameworks (vue, svelte, solid) and potentially for useCompletion as well.

I will take the time to make changes to the points mentioned.

[fribble186]

I like this PR. However, it needs to be changed for all ui frameworks (vue, svelte, solid) and potentially for useCompletion as well.

Thank you for your feedback!

I have made the requested changes and updated the implementation for all UI frameworks (Vue, Svelte, Solid) and also for useCompletion. Please review the updated PR and let me know if there are any further adjustments needed.

Additionally, while making these changes, I noticed an issue: the handleSubmit method returned by the useChat hook in React includes a metadata parameter, but the handleSubmit definition in the UseChatHelpers type does not include this parameter. It seems there is an inconsistency in the type definitions. Could you please confirm if this is an issue that needs to be addressed? @lgrammel

Thanks again!

[lgrammel]

Superseeded by #2073