VueJS - Vue 3 Composition API: Setup and Lifecycle

Detailed Guide to Setup and Lifecycle Hooks in the Composition API

The Composition API in Vue 3 provides a flexible and powerful way to organize component logic. This guide explores the setup function and lifecycle hooks, offering a comprehensive understanding of how to use them effectively in your Vue 3 applications.

The Setup Function

The setup function is called before the component is created. It serves as a replacement for the data, computed, methods, and lifecycle hooks options in the Options API. The setup function receives two arguments: props and context.

// MyComponent.vue



                

Using Lifecycle Hooks

Lifecycle hooks in the Composition API provide similar functionality to the Options API. They allow you to perform actions at specific stages of a component's lifecycle. Common lifecycle hooks include onMounted, onUpdated, and onUnmounted.

// MyComponent.vue



                

Accessing Props and Context

The setup function receives two arguments: props and context. The props argument provides access to the component's props, while the context argument provides access to the component's attributes, slots, and emit function.

// MyComponent.vue



                

Advanced Lifecycle Hooks

Vue 3 provides additional lifecycle hooks that can be used for more advanced scenarios:

• onBeforeMount: Called before the component is mounted.
• onBeforeUpdate: Called before the component is updated.
• onBeforeUnmount: Called before the component is unmounted.
• onRenderTracked: Called when a reactive dependency is tracked during rendering.
• onRenderTriggered: Called when a reactive dependency triggers a re-render.

// MyComponent.vue



                

Best Practices

Follow these best practices when using the Composition API's setup function and lifecycle hooks:

• Organize Related Logic: Group related pieces of logic together to improve readability and maintainability.
• Minimize Side Effects: Keep side effects to a minimum and use lifecycle hooks appropriately to manage them.
• Leverage Composables: Extract reusable logic into composable functions to promote code reuse and separation of concerns.
• Test Thoroughly: Test your components and composable functions thoroughly to ensure they behave as expected in different scenarios.

Summary

This guide provided a detailed overview of the setup function and lifecycle hooks in the Vue 3 Composition API. By understanding and leveraging these features, you can create more flexible, maintainable, and reusable component logic in your Vue 3 applications.