Why deep reactivity understanding matters in Vue - See It in Action

Why Deep Reactivity Understanding Matters in Vue

📖 Scenario: You are building a simple Vue 3 app to track a user's profile information. You want to see how Vue's reactivity system updates the UI when nested data changes.

🎯 Goal: Build a Vue 3 component that uses a reactive object with nested properties. Update nested properties and see the UI update automatically. This will help you understand why deep reactivity matters in Vue.

📋 What You'll Learn

Use Vue 3 Composition API with <script setup>

Create a reactive object with nested properties

Add a button to update a nested property

Display nested property values in the template

Observe UI updates when nested data changes

💡 Why This Matters

🌍 Real World

Understanding deep reactivity helps you build dynamic Vue apps where nested data changes reflect instantly in the UI, such as user profiles, settings, or complex forms.

💼 Career

Vue developers must grasp deep reactivity to debug UI update issues and write efficient, maintainable reactive code in real projects.

1

Create a reactive user profile object

Inside <script setup>, create a reactive object called userProfile with these exact nested properties: name set to "Alice", and address which itself is an object with city set to "Wonderland".

Vue

// Create reactive userProfile object with nested properties
// Your code here



  

Need a hint?

Use Vue's reactive function to create a reactive object with nested properties.

2

Add a button to update the nested city property

Add a function called changeCity inside <script setup> that changes userProfile.address.city to "Dreamland". Also add a button in the template with @click="changeCity" and label it Change City.

Vue

import { reactive } from 'vue'

const userProfile = reactive({
  name: "Alice",
  address: {
    city: "Wonderland"
  }
})

// Add changeCity function here
// Your code here



  
  

Need a hint?

Create a function to update the nested city property and a button to trigger it.

3

Display the nested city property in the template

Inside the template, add a paragraph that shows the text Current city: followed by the value of userProfile.address.city using Vue's interpolation syntax.

Vue

import { reactive } from 'vue'

const userProfile = reactive({
  name: "Alice",
  address: {
    city: "Wonderland"
  }
})

function changeCity() {
  userProfile.address.city = "Dreamland"
}



  Change City
  
  

Need a hint?

Use double curly braces {{ }} to show the nested city property in the template.

4

Add the user name display and wrap content in a semantic section

In the template, add a heading <h2> that displays User: followed by userProfile.name. Wrap the button and paragraph inside a <section> element with aria-label="User Profile Section" for accessibility.

Vue

import { reactive } from 'vue'

const userProfile = reactive({
  name: "Alice",
  address: {
    city: "Wonderland"
  }
})

function changeCity() {
  userProfile.address.city = "Dreamland"
}



  
  
  

Need a hint?

Use semantic HTML and add an aria-label for accessibility. Display the user name in an <h2> heading.