Vue 3 Composition API Lifecycle Hooks

Lately I’ve been working with Vue 3, and I figured it would be helpful to share more insight into this JavaScript framework the more I delve into it. When it comes to Vue’s lifecycle hooks, I think it’s useful to understand when and where you can use them.

Vue 3 lifecycle hooks are special functions that allow you to run code at specific moments in the life of a Vue component. Each hook corresponds to a different phase in the component’s existence, giving you the ability to perform tasks or respond to events at specific times. Let’s break down what each hook does:

onBeforeMount

For tasks that should complete just before the component is mounted, use onBeforeMount. This hook is ideal for actions like pre-fetching data or performing any operations that need to be completed before the component becomes visible.

import { onBeforeMount } from 'vue';

onBeforeMount(() => {
  // Tasks to perform just before mounting
});

onMounted

To interact with the DOM or execute operations after the component has been successfully mounted, use the onMounted lifecycle hook. This is a great time to access and manipulate DOM elements.

import { onMounted } from 'vue';

onMounted(() => {
  // Access and manipulate the DOM
});

onUpdated

When responsiveness to changes in state or props is crucial after an update, you can utilize onUpdated. This hook allows you to react dynamically to modifications in the component’s state or props, enabling you to trigger side effects or additional logic during re-renders.

import { onUpdated } from 'vue';

onUpdated(() => {
  // React to changes in state or props
});

onBeforeUnmount

For cleanup tasks and resource release before a component is unmounted, use onBeforeUnmount. This hook ensures that your component gracefully removes any resources acquired during its lifecycle.

import { onBeforeUnmount } from 'vue';

onBeforeUnmount(() => {
  // Cleanup tasks before unmounting
});

onErrorCaptured

For handling errors occurring within the component’s lifecycle, turn to onErrorCaptured. This hook allows you to catch and manage errors internally or propagate them to a higher level for comprehensive error handling.

import { onErrorCaptured } from 'vue';

onErrorCaptured((error, instance, info) => {
  // Handle errors within the component
});

Megan Coyle