📖 Scenario: You are building a simple Vue app that shows a list of products with their prices. You want to understand why Vue's performance features help your app stay fast and smooth, especially when the list grows.
🎯 Goal: Create a Vue component that displays a list of products. Then add a reactive variable to filter expensive products. Finally, use Vue's computed property to optimize filtering for better performance.
📋 What You'll Learn
Create a reactive array called products with 5 product objects, each having name and price properties.
Add a reactive variable called priceThreshold set to 50.
Use a computed property called expensiveProducts that returns products with price greater than priceThreshold.
Display the expensiveProducts list in the template with product names and prices.
💡 Why This Matters
🌍 Real World
Filtering and displaying lists of items is common in shopping sites, dashboards, and data apps. Efficient updates keep the user experience smooth.
💼 Career
Understanding Vue's reactivity and computed properties is essential for frontend developers building fast, maintainable web apps.
Progress0 / 4 steps
1
Set up the products data
Create a reactive array called products inside the setup() function with these exact objects: { name: 'Pen', price: 10 }, { name: 'Notebook', price: 25 }, { name: 'Backpack', price: 60 }, { name: 'Calculator', price: 80 }, { name: 'Desk Lamp', price: 45 }.
Vue
Hint
Use ref from Vue to create a reactive array inside setup().
2
Add a price threshold variable
Inside the setup() function, create a reactive variable called priceThreshold and set it to 50.
Vue
Hint
Use ref to create a reactive variable for the price threshold.
3
Create a computed property for filtering
Inside the setup() function, create a computed property called expensiveProducts that returns products with price greater than priceThreshold.value. Use Vue's computed from vue.
Vue
Hint
Import computed from Vue and use it to create a reactive filtered list.
4
Display the filtered products in the template
In the , use a v-for directive to loop over expensiveProducts and display each product's name and price inside a <li> element. Wrap the list in a <ul>.
Vue
Hint
Use v-for with a unique :key to loop over expensiveProducts and show each product's name and price.
Practice
(1/5)
1. Why is Vue performance important for web applications?
easy
A. It keeps the app smooth and users happy.
B. It makes the app look colorful.
C. It increases the size of the app files.
D. It removes all animations from the app.
Solution
Step 1: Understand user experience impact
Good performance means the app runs smoothly without delays, which keeps users happy.
Step 2: Identify the role of performance
Performance does not affect colors or file size directly but affects how fast and responsive the app feels.
Final Answer:
It keeps the app smooth and users happy. -> Option A
Quick Check:
Vue performance = smooth app and happy users [OK]
Hint: Performance means smooth and happy users, not looks [OK]
Common Mistakes:
Confusing performance with visual design
Thinking performance increases app size
Assuming performance removes animations
2. Which Vue feature helps improve performance by updating only what changes?
easy
A. Using global variables
B. Direct DOM manipulation
C. Reactive data binding
D. Inline CSS styles
Solution
Step 1: Identify Vue's reactive system
Vue uses reactive data binding to track changes and update only affected parts of the page.
Step 2: Compare other options
Direct DOM manipulation is manual and less efficient; global variables and inline styles do not improve update efficiency.
Final Answer:
Reactive data binding -> Option C
Quick Check:
Reactive data = efficient updates [OK]
Hint: Reactive data updates only changed parts [OK]
Common Mistakes:
Choosing direct DOM manipulation instead of reactive binding
Confusing global variables with performance features
Thinking inline styles affect update efficiency
3. What will be the output behavior of this Vue component when the button is clicked?