When working with APIs in your applications, you often need to manage the state of the data returned from those API calls. Immer is a powerful library that allows you to work with immutable state in a more convenient and intuitive manner. In this blog post, we will discuss some strategies for handling API calls with Immer, making your code cleaner and easier to maintain.

1. Initializing the state

Before making an API call, it is important to initialize the state for the data you expect to receive. In this example, let’s assume we have an array called users that will store the user data fetched from the API:

import produce from "immer";

const initialState = {
  loading: false,
  error: null,
  users: [],
};

2. Handling loading and error states

When making an API call, there are three important states to consider: loading, success, and error. Immer allows you to handle these states smoothly. Here’s an example implementation:

const reducer = produce((draft, action) => {
  switch (action.type) {
    case "FETCH_USERS_REQUEST":
      draft.loading = true;
      draft.error = null;
      break;
    case "FETCH_USERS_SUCCESS":
      draft.loading = false;
      draft.users = action.payload;
      break;
    case "FETCH_USERS_FAILURE":
      draft.loading = false;
      draft.error = action.payload;
      break;
    default:
      break;
  }
}, initialState);

In this code snippet, we use Immer’s produce function to create an immutable copy of the state and make any necessary updates. With Immer, we can directly modify the draft state without worrying about creating new copies manually.

3. Updating state with API response

Once the API call is successful, we need to update the state with the data received. Here’s an example of how to update the users array with the API response:

dispatch({ type: "FETCH_USERS_REQUEST" });

axios
  .get("/api/users")
  .then((response) => {
    dispatch({ type: "FETCH_USERS_SUCCESS", payload: response.data });
  })
  .catch((error) => {
    dispatch({ type: "FETCH_USERS_FAILURE", payload: error.message });
  });

In this code, we dispatch a request action to set the loading state to true. Then we make the API call using a library like axios and dispatch the success or failure actions based on the response.

4. Modifying state with Immer

If you need to modify the state further based on user actions, Immer provides a convenient way to do so. Here’s an example of adding a new user to the users array:

const addUser = (user) => {
  dispatch({ type: "ADD_USER_REQUEST" });

  axios
    .post("/api/users", user)
    .then((response) => {
      dispatch({ type: "ADD_USER_SUCCESS", payload: response.data });

      // Modify the state further
      dispatch({ type: "MODIFY_USER", payload: response.data });
    })
    .catch((error) => {
      dispatch({ type: "ADD_USER_FAILURE", payload: error.message });
    });
};

In this code, we dispatch an action to add a new user. Once the API call is successful, we dispatch the success action and modify the state further by dispatching a “MODIFY_USER” action.

Conclusion

Using Immer in combination with API calls can greatly simplify state management in your applications. By leveraging Immer’s produce function, you can handle loading states, update data from APIs, and modify the state with ease. This leads to cleaner and more maintainable code. Happy coding!

#APIs #Immer