In modern web applications, it’s crucial to provide users with a responsive and seamless experience. One common way to achieve this is by using optimistic updates. Optimistic updates allow you to immediately update the UI with the user’s action while asynchronously sending the request to update the server. This gives users the perception that their changes have been instantly applied, even before the server responds.

What is Redux Toolkit?

Redux Toolkit is a library that simplifies common Redux patterns and helps you write Redux logic more efficiently. It provides a set of utilities and abstractions like createSlice and createAsyncThunk that make it easier to work with Redux.

Working with Optimistic Updates using Redux Toolkit

To implement optimistic updates using Redux Toolkit, you can follow these steps:

1. Create a Redux slice using the createSlice function from Redux Toolkit. This slice will contain the state and reducer functions for handling the optimistic updates.

const todosSlice = createSlice({
  name: 'todos',
  initialState: [],
  reducers: {
    addTodo: {
      reducer(state, action) {
        // Optimistically update the local state
        state.push(action.payload);
      },
      prepare(payload) {
        // Generate a unique ID for the new todo item
        const id = uuidv4();

        // Return the prepared action with the payload and generated ID
        return { payload: { id, ...payload } };
      }
    },
  },
});

1. Define an async thunk using the createAsyncThunk function from Redux Toolkit. This thunk will handle the request to update the server.

export const saveTodo = createAsyncThunk(
  'todos/saveTodo',
  async (todo, { dispatch }) => {
    try {
      const response = await api.saveTodoToServer(todo);

      // Update the local state with the server response
      dispatch(todosSlice.actions.addTodo(response));
    } catch (error) {
      // Handle error if the server request fails
    }
  }
);

1. Use the optimistic update in your component. When the user triggers an action, dispatch the optimistic update action from the Redux slice and then call the async thunk to update the server.

import { useDispatch } from 'react-redux';

const AddTodoForm = () => {
  const dispatch = useDispatch();

  const handleSubmit = (event) => {
    event.preventDefault();

    const formData = new FormData(event.target);
    const todo = {
      title: formData.get('title'),
      description: formData.get('description'),
    };

    // Dispatch the optimistic update action
    dispatch(todosSlice.actions.addTodo.prepare(todo));

    // Call the async thunk to update the server
    dispatch(saveTodo(todo));
  };

  return (
    <form onSubmit={handleSubmit}>
      {/* Form fields */}
    </form>
  );
};

By using Redux Toolkit’s createSlice and createAsyncThunk, you can easily implement optimistic updates in your Redux application. This approach provides a smooth user experience by immediately reflecting the local changes while ensuring that the server state is eventually synchronized.

#redux #optimistic