Computed properties are a powerful feature in Vue.js that allow you to define complex, derived data based on existing data in your application. They help you keep your code clean, organized, and more efficient by automatically updating the derived data when the dependencies change. In this blog post, we will explore how to work with computed properties in combination with Immer, a popular library for immutable state management.

What is Immer?

Immer is a library that simplifies the process of working with immutable data in JavaScript. It allows you to write code that looks like you’re directly modifying data, but under the hood, it creates a new copy of the data, keeping the original data intact. This makes it easy to work with immutable data structures and helps ensure your data remains unchanged during the application’s lifecycle.

Why use Computed Properties?

Computed properties in Vue.js are a great way to derive data based on existing data. They are especially useful when working with complex data transformations or calculations. By using computed properties, you can keep your template code cleaner by abstracting away the logic and calculations into separate properties. Additionally, computed properties are reactive, meaning they will automatically update when their dependencies change.

Combining Immer and Computed Properties

Immer can be seamlessly integrated with Vue.js to create computed properties that work with immutable data. Here’s an example of how you can achieve this:

<template>
  <div>
    <p></p>
  </div>
</template>

<script>
import { produce } from 'immer';
import { computed, reactive } from 'vue';

export default {
  setup() {
    const state = reactive({
      firstName: 'John',
      lastName: 'Doe',
    });

    const fullName = computed(() => {
      return produce(state, (draft) => {
        draft.fullName = `${draft.firstName} ${draft.lastName}`;
      });
    });

    return { fullName };
  },
};
</script>

In this example, we have a reactive state object that holds the firstName and lastName properties. We then define a computed property called fullName that uses the produce function from Immer to calculate the full name based on the reactive state. The produce function ensures that any modifications made within the callback function are applied to a new copy of the state object, preserving immutability.

By using this approach, we can work with derived data in a reactive manner while leveraging the benefits of Immer’s immutability. Any changes made to the firstName or lastName properties will automatically trigger the recalculation of the fullName property, thanks to Vue.js reactivity system.

Conclusion

Using computed properties in combination with Immer can greatly simplify your code and make it more efficient. You can leverage the power of Vue.js’ reactivity system while ensuring the immutability of your data with Immer. This combination allows for clean, organized, and performant code. So go ahead and start exploring the possibilities of computed properties and immutability in your Vue.js applications! #VueJS #Immer