In today’s blog post, we will explore how to integrate Immer, a powerful immutable state management library, into a MobX project. Immer provides an elegant way to work with immutable data structures and simplifies the process of managing complex application states. MobX, on the other hand, is a popular library for state management with observable objects, allowing you to track state changes and automatically update the UI.

Why combine Immer with MobX?

Integrating Immer with MobX can bring a lot of benefits to your project. Here are a few reasons why you might consider using both libraries together:

1. Simplified state updates: Immer’s produce function allows you to update your state in a mutable way while still ensuring immutability. This can greatly simplify the process of updating MobX observable objects, reducing boilerplate code and improving code readability.
2. Improved performance: Immer uses a copy-on-write mechanism, which means it only creates new copies of the state objects if they have been modified. This can lead to improved performance by avoiding unnecessary object cloning.
3. Time-travel debugging: By using Immer, you can easily implement time-travel debugging in your MobX application. Immer’s produceWithPatches function provides the ability to track changes made to the state over time, enabling powerful debugging capabilities.

Integrating Immer into a MobX project

To integrate Immer into your MobX project, follow these steps:

Step 1: Install the required dependencies

Start by installing the necessary dependencies. Open your terminal and navigate to your project directory:

npm install mobx immer

Step 2: Create a MobX store

Create a MobX store using the @observable decorator to define the state properties we want to make observable:

import { observable } from "mobx";

class MyStore {
  @observable data = {
    counter: 0,
    todos: [],
  };
}

const store = new MyStore();
export default store;

Step 3: Update MobX state using Immer

Now we can start using Immer to update our MobX state. Import the produce function from Immer and use it to create a new state draft inside MobX actions:

import { observable, action } from "mobx";
import produce from "immer";

class MyStore {
  @observable data = {
    counter: 0,
    todos: [],
  };

  @action
  updateData() {
    this.data = produce(this.data, (draft) => {
      draft.counter++;
      draft.todos.push("New todo");
    });
  }
}

const store = new MyStore();
export default store;

In the above code, we have used the @action decorator from MobX to create an action method called updateData. Inside this method, we call produce and pass the current state (this.data) and a draft function. The draft function is where you can make changes to the state in a mutable way.

Step 4: Accessing state changes from MobX

If you want to access the state changes from MobX, such as tracking the patches or logging state modifications, you can use Immer’s produceWithPatches function:

import { observable, action } from "mobx";
import produce, { produceWithPatches } from "immer";

// ...

class MyStore {
  // ...

  @action
  updateData() {
    const [newData, patches] = produceWithPatches(this.data, (draft) => {
      draft.counter++;
      draft.todos.push("New todo");
    });

    console.log(patches);
    this.data = newData;
  }
}

// ...

In the updated code snippet, we capture the produced newData and patches from the produceWithPatches function. You can then log the patches or perform any custom logic based on the changes.

Conclusion

By combining Immer with MobX, we can simplify our state updates and benefit from the best of both libraries. Immer allows us to work with immutable data structures in a mutable way, while MobX tracks these changes and updates the UI automatically. This integration brings improved performance and enables powerful debugging capabilities in our MobX projects. Give it a try in your next project and experience the ease of managing complex application states!

If you found this blog post helpful, please share it with the community. Happy coding!

#Immer #MobX