Lifecycle Hooks Vue 3

In Vue 3, Lifecycle Hooks are a set of functions that are triggered at different life cycle stages of a component, allowing you to execute code in a specific component state. Lifecycle hooks in Vue 3 are similar to those in Vue 2, but with a few differences. Below are the main lifecycle hooks in Vue 3 and their explanations:

1. setup : This is a new hook introduced in Vue 3, which is called before the component is created. setupThe function is the entry point of the component. It can perform some setup work, such as initializing responsive data, introducing other modules, and setting up listeners. In setupa function, you can expose some variables, methods, etc. by returning an object. These exposed contents can be used in component templates.

2. beforeCreate : Called before the component instance is created. At this time, the component's properties and methods have not been initialized.

3. created : Called immediately after the component instance is created. At this point, the component's properties and methods have been initialized, but the DOM has not yet been mounted.

4. beforeMount : Called before the component is mounted to the DOM. At this point, the component's template has been compiled but has not yet been inserted into the page.

5. mounted : Called after the component is mounted to the DOM. At this point, the component's template has been inserted into the page and DOM operations can be performed.

6. beforeUpdate : Called before the component is updated, before data changes cause the DOM to be updated.

7. updated : Called after the component is updated, after data changes cause the DOM to be updated.

8. beforeUnmount : Called before the component instance is destroyed. You can perform some cleanup work here, such as unsubscribing, clearing timers, etc.

9. unmounted : Called after the component instance is destroyed. At this point all content of the component will be destroyed, including DOM elements and listeners.

10. errorCaptured : Called when an error occurs in the child component. Can be used to catch and handle errors in child components.

It should be noted that in Vue 3, beforeDestroyand destroyedthe two life cycle hooks that existed in Vue 2 have been deprecated and replaced by beforeUnmountand unmounted.

It should be noted that when using the Composition API, setupmany lifecycle hook functions can be used directly in the function, such as the or data setupreturned in the component will be automatically updated throughout the life cycle of the component.refreactive

In summary, lifecycle hooks allow specific operations to be performed at different component lifecycle stages, thereby controlling and managing the behavior and state of the component. When writing Vue 3 applications, you can use these lifecycle hooks as needed to implement your business logic.