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Vue.js Lifecycle Hooks

Continuing our Vue.js Journey: Lifecycle Hooks

Welcome back to our Vue.js adventure! In this session, we'll delve into lifecycle hooks, a crucial aspect of Vue.js that allows us to respond to various stages in a component's lifecycle.

What are Lifecycle Hooks?

Lifecycle hooks are special methods in Vue.js components that allow us to perform specific actions at different stages of a component's lifecycle.

// Example:
created() {
  // Code to run when the component is created
},

Why use Lifecycle Hooks?

  • Manage component state and perform data fetching.
  • Control component behavior at different stages.
  • Perform cleanup tasks when components are destroyed.
  • Types of Lifecycle Hooks

    Vue.js provides various lifecycle hooks to handle different stages:

    • Creation Hooks: beforeCreate(), created()
    • Mounting Hooks: beforeMount(), mounted()
    • Update Hooks: beforeUpdate(), updated()
    • Destruction Hooks: beforeDestroy(), destroyed()
    • Other Hooks: activated(), deactivated(), errorCaptured(), serverPrefetch()

    The beforeCreate() Hook

    Called before the component is created. Use it for tasks like:

    • Setting default data values using this.data = {}.
    • Initializing properties using this.propertyName = value.

    The created() Hook

    Called immediately after the component is created. Use it for tasks like:

    • Making API calls using axios or Vue resource.
    • Setting up event listeners using this.$on().

    The beforeMount() Hook

    Called just before the Vue component has been mounted to the DOM. Use it for tasks like:

    • Performing DOM manipulations using Vue's reactivity system.
    • Making final preparations before the component becomes visible.

    The mounted() Hook

    Called immediately after the component has been mounted to the DOM. Use it for tasks like:

    • Accessing the DOM and interacting with elements.
    • Setting up event listeners using Vue's event system this.$emit().

    The beforeUpdate() Hook

    Called before the component starts updating. Use it for tasks like:

    • Performing calculations or data transformation.
    • Updating the UI based on changed props or state.

    The updated() Hook

    Called immediately after the component has updated. Use it for tasks like:

    • Performing post-update operations.
    • Triggering additional actions based on updated props or state.

    The beforeDestroy() Hook

    Called before the Vue component is destroyed. Use it for tasks like:

    • Cleaning up event listeners using this.$off().
    • Canceling ongoing processes, such as API calls using `axios.cancel()`.

    The destroyed() Hook

    Called after the Vue component is destroyed. Use it for tasks like:

    • Performing final cleanup, such as removing references to the component.
    • Unbinding event listeners and deleting any created DOM elements.

    The activated() Hook

    Called when a Vue component is activated (for components in a <keep-alive> block). Use it for tasks like:

    • Re-initializing data or state when the component is brought back to life.
    • Refreshing data from an API or database.

    The deactivated() Hook

    Called when a Vue component is deactivated (for components in a <keep-alive> block). Use it for tasks like:

    • Pausing any ongoing processes, such as timers or animations.
    • Saving component state before it is removed from the DOM.

    The errorCaptured() Hook

    Called when an error occurs in a child component. Use it for tasks like:

    • Logging the error message using console.error() or a custom error handling service.
    • Displaying an error message to the user in a modal or toast.

    The serverPrefetch() Hook

    Called on the server-side when using Vue's server-side rendering (SSR). Use it for tasks like:

    • Fetching data from a database or API.
    • Pre-rendering the component's HTML, which can improve performance on the client-side.

    Next Up: Vue.js Reactive Data Binding

    In our next session, we'll dive into reactive data binding in Vue.js, exploring how to bind data to the DOM and seamlessly update the UI as your data changes. Follow us for more exciting insights!