Vue 3 Features and Composition API
Welcome to this comprehensive, student-friendly guide on Vue 3 and the Composition API! 🎉 If you’re just starting out or looking to deepen your understanding, you’re in the right place. Vue 3 brings a lot of exciting features to the table, and the Composition API is one of the most powerful tools for building scalable and maintainable applications. Let’s dive in!
What You’ll Learn 📚
- Core concepts of Vue 3 and the Composition API
- Key terminology and definitions
- Step-by-step examples from simple to complex
- Common questions and clear answers
- Troubleshooting tips for common issues
Introduction to Vue 3 and the Composition API
Vue.js is a progressive JavaScript framework used for building user interfaces. With the release of Vue 3, the framework introduced several new features, including the Composition API. This API provides a more flexible and powerful way to organize your code, especially in larger applications.
Key Terminology
- Vue Instance: The root of a Vue application, where you define the application logic.
- Composition API: A set of APIs that allow you to organize your component logic using functions.
- Reactive: A system that automatically updates the UI when the underlying data changes.
Getting Started with the Simplest Example
Example 1: Basic Vue 3 Setup
// index.html
Vue 3 Basic Example
{{ message }}
In this example, we create a simple Vue application that displays a message. We use the createApp function to initialize the app and the mount method to attach it to the DOM element with the id ‘app’.
Expected Output: ‘Hello, Vue 3!’ displayed on the webpage.
Progressively Complex Examples
Example 2: Using the Composition API
// index.html
Vue 3 Composition API Example
{{ count }}
Here, we use the Composition API to manage state and behavior. The ref function creates a reactive reference for the count variable. The increment function updates the count, demonstrating reactivity.
Expected Output: A counter that increments by 1 each time the button is clicked.
Example 3: Reactive Properties
// index.html
Vue 3 Reactive Properties
{{ doubleCount }}
This example introduces computed properties, which automatically update based on reactive dependencies. The doubleCount property is computed from the count value, showcasing how Vue manages dependencies for you.
Expected Output: Displays double the count value, updating as the button is clicked.
Common Questions and Answers
- What is the main advantage of the Composition API?
The Composition API provides a more flexible and organized way to manage component logic, especially beneficial for larger applications.
- How does reactivity work in Vue 3?
Reactivity in Vue 3 is achieved through the ref and reactive functions, which track changes and update the UI automatically.
- Can I use the Composition API with Vue 2?
No, the Composition API is a feature introduced in Vue 3.
Troubleshooting Common Issues
Ensure you are using Vue 3 when trying to use the Composition API, as it is not available in Vue 2.
If your reactive properties aren’t updating the UI, check that you are using ref or reactive correctly and that you are accessing the value property of refs.
Practice Exercises
- Create a Vue 3 app that uses the Composition API to manage a list of items. Add functionality to add and remove items.
- Experiment with computed properties to create a property that filters the list based on a search query.
For more information, check out the official Vue 3 documentation.