How to Transform Your Vue 3 Code from Options API to Composition API

Unlock the full potential of Vue 3 by learning how to seamlessly convert your `Options API` code to `Composition API`. This guide provides clear examples and step-by-step instructions for a smooth transition.
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This video is based on the question https://stackoverflow.com/q/73808898/ asked by the user 'bxeom' ( https://stackoverflow.com/u/17952093/ ) and on the answer https://stackoverflow.com/a/73809244/ provided by the user 'Stephen Gilboy' ( https://stackoverflow.com/u/621827/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Transforming Your Vue 3 Code: Options API to Composition API

In the world of modern web development, Vue.js stands out as a powerful JavaScript framework for building user interfaces. With the introduction of Vue 3, developers gained access to a new way of structuring their code through the Composition API. If you're familiar with the Options API and wondering how to migrate your code, you've come to the right place. This post will guide you through the process of converting your existing Options API code to the Composition API in Vue 3.

Understanding the Options API vs. Composition API

Before diving into the transformation process, it's important to understand the key differences between the two APIs:

Options API: This is the traditional way of defining components in Vue. It uses an object-based syntax where you define data, methods, and lifecycle hooks as separate properties.

Composition API: Introduced in Vue 3, this API allows for a more flexible composition of logic and state management inside components. It provides a more functional approach, making it easier to organize and reuse code.

The Original Options API Code

Let's take a look at the original code written in the Options API. The purpose of this code is to manage a simple form input field, resetting its value upon clicking a button.

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Breakdown of the Original Code

data: This section contains the state of the component, which in this case is a single property text initialized to an empty string.

methods: Here, the resetForm function clears the text field when the button is clicked. The function prevents the default form submission with e.preventDefault() and resets the value of text.

Converting to the Composition API

Now, let's see how we can rewrite the above code using the Composition API.

Step-by-Step Transformation

Script Setup: Start by using the <script setup> syntax. This allows for cleaner code and better performance.

Imports: Import the ref function from Vue, which lets you create reactive state variables.

Define Reactive State: Replace data with a ref, initializing the text.

Define Methods: Instead of placing methods in a separate methods object, define them directly in the setup function or inside <script setup>.

Final Composition API Code

Here’s how the complete code looks when converted to the Composition API:

Using <script setup>

[[See Video to Reveal this Text or Code Snippet]]

Using the setup function in separate files

[[See Video to Reveal this Text or Code Snippet]]

Key Changes Made

The data function is replaced with a ref that holds the state.

The resetForm method is defined as a regular function instead of being part of a methods object.

Data is accessed using text.value, which is the reactive property in the Composition API.

Conclusion

Transitioning from the Options API to the Composition API in Vue 3 might seem daunting at first, but with clear examples and an understanding of both APIs, it can be an intuitive process. By leveraging the power of the Composition API, you can create more organized, reusable, and maintainable code. Happy coding!