Immer is a powerful library that allows you to work with immutable data structures in a more intuitive way. It simplifies the process of managing state by providing a convenient API to create mutable updates on immutable data. One feature of Immer that is often overlooked is its ability to work with computed properties. In this post, we will explore how to leverage computed properties in Immer to make our code more elegant and efficient.

Computed properties are derived values that are calculated based on other properties of an object. They provide an easy way to encapsulate complex logic and simplify our code by abstracting away the details of the calculation. By using computed properties, we can avoid redundant calculations and improve the performance of our code.

To work with computed properties in Immer, we can use the produce function along with the set and get functions provided by Immer. Let’s see an example:

import produce, { set, get } from 'immer';

const state = {
  firstName: 'John',
  lastName: 'Doe',
  fullName: '',
};

const newState = produce(state, (draft) => {
  set(draft, 'fullName', `${get(draft, 'firstName')} ${get(draft, 'lastName')}`);
});

In the above example, we have an initial state object with firstName, lastName, and fullName properties. To update the fullName property based on the firstName and lastName, we use the set function to assign the new value to the computed property. We can retrieve the values of the firstName and lastName properties using the get function.

This approach allows us to separate the logic for updating derived values from the rest of our code. We can easily modify the computation logic without affecting other parts of our application. Additionally, Immer ensures that only the modified parts of the state are updated, providing better performance.

Another useful feature of computed properties in Immer is the ability to compute values based on dynamic or nested properties. We can use nested paths with the set and get functions to access properties deep within the state object. Here’s an example:

const state = {
  user: {
    firstName: 'John',
    lastName: 'Doe',
    fullName: '',
  },
};

const newState = produce(state, (draft) => {
  set(draft, 'user.fullName', `${get(draft, 'user.firstName')} ${get(draft, 'user.lastName')}`);
});

In this example, we have a nested user object within our state. We can update the computed property user.fullName by providing the nested path to the set and get functions.

By utilizing computed properties in Immer, we can improve the readability, maintainability, and performance of our code. The abstraction provided by Immer makes it easier to work with derived values, ensuring that our code remains clean and efficient.

#Immer #ComputedProperties