Mastering Vue 3: A Comprehensive Guide to Building Modern Web Applications <Part 6 />
Tags: webdev, javascript, programming, vue
Published: 2024-02-03 16:35:42

#### Content:
1. [Mastering Vue 3 - Part 1 [Introduction and key features]](https://dev.to/hanytaha61/mastering-vue-3-a-comprehensive-guide-to-building-modern-web-applications-part-1--c75)

[2. Mastering Vue 3 - Part 2 [Benefits of using Vue 3 for web development]](https://dev.to/hanytaha61/mastering-vue-3-a-comprehensive-guide-to-building-modern-web-applications-part-2--1k0l)

[3. Mastering Vue 3 - Part 3 [Template syntax in Vue 3]](https://dev.to/hanytaha61/mastering-vue-3-a-comprehensive-guide-to-building-modern-web-applications-part-3--fde)

[4. Mastering Vue 3 - Part 4 [Reactivity Fundamentals]](https://dev.to/hanytaha61/mastering-vue-3-a-comprehensive-guide-to-building-modern-web-applications-19c0)

[5. Mastering Vue 3 - Part 5 [Class and Style Bindings]](https://dev.to/hanytaha61/mastering-vue-3-a-comprehensive-guide-to-building-modern-web-applications-16g)

**6. Mastering Vue 3 - Part 6 [Lifecycle Hooks]**

[7. Mastering Vue 3 - Part 7 [Understanding components in Vue 3]](https://dev.to/hanytaha61/mastering-vue-3-a-comprehensive-guide-to-building-modern-web-applications-3nnd)

[8. Mastering Vue 3 - Part 8 [Installing Vue project and file structure]](https://dev.to/hanytaha61/mastering-vue-3-a-comprehensive-guide-to-building-modern-web-applications-17ge)

[9. Mastering Vue 3 - Part 9 [Vue Router in Vue 3]](https://dev.to/hanytaha61/mastering-vue-3-a-comprehensive-guide-to-building-modern-web-applications-5d1p)

[10. Mastering Vue 3 - Part 10 [Animation in Vue 3]](https://dev.to/hanytaha61/mastering-vue-3-a-comprehensive-guide-to-building-modern-web-applications-4ig2)

[11. Mastering Vue 3 - Part 11 [State Management with Pinia]](https://dev.to/hanytaha61/mastering-vue-3-a-comprehensive-guide-to-building-modern-web-applications-53gh)

[12. Mastering Vue 3 - Part 12 [Teleport in Vue 3]]
(https://dev.to/hanytaha61/mastering-vue-3-a-comprehensive-guide-to-building-modern-web-applications-5h64)

[13. Mastering Vue 3 - Part 13 [Working with API Calls ]](https://dev.to/hanytaha61/mastering-vue-3-a-comprehensive-guide-to-building-modern-web-applications-5h64)

[14. Mastering Vue 3 - Part 14 [Forms and Form Validation ]](https://dev.to/hanytaha61/mastering-vue-3-a-comprehensive-guide-to-building-modern-web-applications-4bhi)

---

## Lifecycle Hooks

In Vue 3, the concept of lifecycle hooks has been replaced with the Composition API, which provides a more flexible and intuitive way to manage component logic. Instead of using specific lifecycle hooks, you can use composition functions to encapsulate and reuse code.

The Composition API introduces a set of functions that can be used inside the setup function of a component to define reactive data, computed properties, methods, and more. These functions are not tied to specific lifecycle stages, but rather allow you to organize your component logic in a more granular and composable way.

Here are some important composition functions available in Vue 3:

**<u>1. **setup function**:</u>**
The `setup` function is the entry point of a component and is called before the component is created. It is where you define reactive data, computed properties, methods, and component setup logic.

```vue
<script>
import { reactive, computed } from 'vue';

export default {
  setup() {
    const state = reactive({
      message: 'Hello, Vue 3!',
      count: 0
    });

    const doubleCount = computed(() => state.count * 2);

    function increment() {
      state.count++;
    }

    return {
      state,
      doubleCount,
      increment
    };
  }
};
</script>
```

In this example, the `setup` function defines reactive data (`state`), a computed property (`doubleCount`), and a method (`increment`).

**<u>2. **onMounted**:</u>**
The `onMounted` function is used to perform actions when the component is mounted to the DOM. It is similar to the `mounted` lifecycle hook in Vue 2.
```vue
<script>
import { onMounted } from 'vue';

export default {
  setup() {
    onMounted(() => {
      console.log('Component mounted');
    });
  }
};
</script>
```
In this example, the `onMounted` function is used to log a message when the component is mounted.

**<u>3. **onUpdated**:</u>**
The `onUpdated` function is used to perform actions when the component is updated and re-rendered. It is similar to the `updated` lifecycle hook in Vue 2.
```vue
<script>
import { onUpdated } from 'vue';

export default {
  setup() {
    onUpdated(() => {
      console.log('Component updated');
    });
  }
};
</script>
```
In this example, the `onUpdated` function is used to log a message when the component is updated.

**<u>4. **onUnmounted**:</u>**
The `onUnmounted` function is used to perform cleanup actions when the component is unmounted from the DOM. It is similar to the `beforeUnmount` lifecycle hook in Vue 2.
```vue
<script>
import { onUnmounted } from 'vue';

export default {
  setup() {
    onUnmounted(() => {
      console.log('Component unmounted');
    });
  }
};
</script>
```
In this example, the `onUnmounted` function is used to log a message when the component is unmounted.

These are just a few examples of the composition functions available in the Composition API. By using these functions, you can organize your component logic in a more modular and reusable way, without being tied to specific lifecycle hooks.
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