[typescript] how to make first argument in mutation function required?

[stefanprobst]

hi, i am trying to make the first argument of the mutation function (i.e. TVariables) returned by useMutation required, rather than optional. how would i do that? this is what i have:

import { useMutation, MutationConfig } from 'react-query';

type Todo = { title: string };

function createTodo(todo: Todo) {
  return fetch('https://jsonplaceholder.typicode.com/posts/', {
    method: 'post',
    body: JSON.stringify(todo),
  }).then((r) => r.json());
}

function useCreateTodo(config?: MutationConfig<Todo, Error, Todo>) {
  return useMutation<Todo, Error, Todo>((todo) => createTodo(todo), config);
}

export default function Page() {
  const [create] = useCreateTodo();
  return (
    <button
      onClick={async () => {
        // FIXME: this should require a Todo as the first argument, but it does not.
        await create();
      }}
    >
      Create
    </button>
  );
}

[TkDodo]

FYI, I think this now tracked here: #1077