Submitting Data

While useFetch is for fetching and displaying data, useSubmit is its counterpart, designed for actions that change data on the server, such as creating, updating, or deleting resources. You use it when you need to trigger a request manually in response to a user event, like clicking a button.

A key feature of useSubmit is that its submit function returns a promise, allowing you to easily perform actions after the submission completes, like resetting a form or showing a notification.

What you'll learn

1. How to use the useSubmit hook to send data to the server.
2. How to handle form submissions for creating and updating data.
3. How to trigger actions like deleting an item.
4. How the submit function works as a promise for easy chaining of actions.
5. How to manage loading states (submitting) to provide user feedback.

Managing a To-Do List

Let's build a complete example of a to-do list application. We'll use useSubmit for all the mutation logic: adding a new to-do, toggling its completion status, and deleting it.

function TodoApp() {
  const { data: todos, loading, revalidate } = useFetch(getTodos);
  const [newTodo, setNewTodo] = React.useState("");

  // 1. Setup submit hooks for each action
  const { submit: addTodo, submitting: isAdding } = useSubmit(createTodo);
  const { submit: updateTodo } = useSubmit(updateTodoRequest);
  const { submit: deleteTodo } = useSubmit(deleteTodoRequest);

  const handleAddTodo = async (e) => {
    e.preventDefault();
    if (!newTodo.trim()) return;

    // The submit function returns a promise
    await addTodo({ data: { title: newTodo, completed: false } });

    // After success, clear the input and refetch the list
    setNewTodo("");
    revalidate();
  };

  const handleToggleTodo = async (todo) => {
    await updateTodo({
      params: { todoId: todo.id },
      data: { completed: !todo.completed },
    });
    revalidate();
  };

  const handleDeleteTodo = async (todoId) => {
    await deleteTodo({ params: { todoId } });
    revalidate();
  };

  if (loading) return <p className="p-4">Loading to-do list...</p>;

  return (
    <div className="border rounded-md">
      <div className="p-4 border-b">
        <h2 className="text-xl font-bold">My To-Do List</h2>
        <form onSubmit={handleAddTodo} className="flex items-center mt-4">
          <input
            type="text"
            value={newTodo}
            onChange={(e) => setNewTodo(e.target.value)}
            placeholder="What needs to be done?"
            className="flex-grow p-2 border rounded-l-md"
          />
          <button
            type="submit"
            disabled={isAdding}
            className="p-2 bg-blue-500 text-white rounded-r-md hover:bg-blue-600 disabled:bg-gray-400"
          >
            {isAdding ? "Adding..." : "Add Todo"}
          </button>
        </form>
      </div>
      <ul className="divide-y divide-gray-200">
        {todos?.map((todo) => (
          <li key={todo.id} className="p-4 flex items-center justify-between">
            <span
              onClick={() => handleToggleTodo(todo)}
              className={`cursor-pointer ${todo.completed ? "line-through text-gray-500" : ""}`}
            >
              {todo.title}
            </span>
            <button onClick={() => handleDeleteTodo(todo.id)} className="text-red-500 hover:text-red-700">
              Delete
            </button>
          </li>
        ))}
      </ul>
    </div>
  );
}

How It Works

1. Setup: We set up separate useSubmit hooks for each mutation: createTodo, updateTodoRequest, and deleteTodoRequest. This keeps the logic for each action clean and separate.
2. Creating: The handleAddTodo function calls addTodo with the new to-do's data. Because submit is a promise, we can await it and then run code after it completes, such as clearing the input field and calling revalidate() to refresh the to-do list.
3. Updating: handleToggleTodo calls updateTodo with the todoId in params and the new completed status in data. We then revalidate to show the change.
4. Deleting: handleDeleteTodo calls deleteTodo with the appropriate todoId and revalidates.
5. Loading State: The submitting boolean (which we aliased to isAdding for the create action) is used to disable the "Add" button while the request is in flight, preventing duplicate submissions.

This example demonstrates how useSubmit can be the backbone for all the interactive, data-changing parts of your application.

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Congratulations!

You are now a pro at submitting data with useSubmit!

• You can perform create, update, and delete operations with ease.
• You know how to use the submit promise to chain actions after a request.
• You can manage loading states to create a responsive and intuitive UI.
• You can revalidate data from useFetch to keep your UI in sync with server changes.