Text interpolation with mustache syntax in Vue - Mini Project: Build & Apply

Text interpolation with mustache syntax

📖 Scenario: You are building a simple Vue app that shows a greeting message to users. The message should update automatically when the data changes.

🎯 Goal: Create a Vue component that uses mustache syntax to display a greeting message stored in the component's data.

📋 What You'll Learn

Use Vue 3 with the Composition API and <script setup>

Create a reactive variable called greeting with the value 'Hello, Vue learner!'

Use mustache syntax {{ greeting }} in the template to show the greeting

Ensure the component is standalone and can be rendered directly

💡 Why This Matters

🌍 Real World

Text interpolation is used in many web apps to show dynamic data like user names, messages, or live updates.

💼 Career

Understanding how to bind data to the UI with mustache syntax is a fundamental skill for Vue developers and frontend engineers.

1

Create the greeting data variable

In the <script setup> section, import ref from 'vue' and create a reactive variable called greeting with the value 'Hello, Vue learner!'.

Vue

  



// Create a reactive variable called greeting with the value 'Hello, Vue learner!'
// Your code here

Hint

Use ref to create a reactive variable in Vue 3 Composition API.

2

Add the template with mustache syntax

In the <template> section, add a <p> tag that displays the greeting variable using mustache syntax {{ greeting }}.

Vue

   tag that shows the greeting using {{ greeting }} -->
  



import { ref } from 'vue'
const greeting = ref('Hello, Vue learner!')

Hint

Use double curly braces {{ }} to show reactive data in Vue templates.

3

Add a button to change the greeting

Below the <p> tag, add a <button> that changes the greeting variable to 'You clicked the button!' when clicked. Use the @click event with an inline arrow function.

Vue

  {{ greeting }}
  
  



import { ref } from 'vue'
const greeting = ref('Hello, Vue learner!')

Hint

Use @click with an arrow function to update reactive data.

4

Make the component standalone

Add the export default { block with name: 'GreetingComponent' and standalone: true below the <script setup> code to make the component standalone.

Vue

  {{ greeting }}
   greeting.value = 'You clicked the button!'">Click me



import { ref } from 'vue'
const greeting = ref('Hello, Vue learner!')

// Add export default with name and standalone true
// Your code here

Hint

Standalone components can be used directly without modules.

Practice

1. What does the mustache syntax {{ message }} do in a Vue template?

easy

A. It displays the value of the variable message inside the HTML.

B. It creates a new variable called message.

C. It comments out the text inside the braces.

D. It runs a JavaScript function named message.

Solution

1. Step 1: Understand mustache syntax purpose

   The mustache syntax {{ }} is used in Vue to insert data values into HTML templates.

2. Step 2: Identify what {{ message }} does

   It shows the current value of the variable named message in the rendered HTML.

3. Final Answer:

   It displays the value of the variable message inside the HTML. -> Option A

4. Quick Check:

   Mustache syntax = display variable value [OK]

Hint: Mustache {{ }} always shows variable content in HTML [OK]

Common Mistakes:

• Thinking it creates variables
• Assuming it runs functions
• Confusing it with comments

2. Which of the following is the correct way to display a variable title inside a Vue template using mustache syntax?

easy

A. [[ title ]]

B. { title }

C. {{ title }}

D. {% title %}

Solution

1. Step 1: Recall Vue interpolation syntax

   Vue uses double curly braces {{ }} to insert variables into templates.

2. Step 2: Match the correct syntax

   Only {{ title }} matches Vue's mustache syntax for interpolation.

3. Final Answer:

   {{ title }} -> Option C

4. Quick Check:

   Vue interpolation = {{ variable }} [OK]

Hint: Vue uses double curly braces {{ }} for interpolation [OK]

Common Mistakes:

• Using single braces instead of double
• Confusing with other template syntaxes
• Using wrong bracket types

3. Given the Vue data: { name: 'Anna' }, what will be rendered by this template?

<div>Hello, {{ name }}!</div>

medium

A. Hello, {{ name }}!

B. Hello, Anna!

C. Hello, name!

D. Hello, !

Solution

1. Step 1: Identify the data value

   The variable name has the value 'Anna'.

2. Step 2: Understand interpolation output

   The mustache syntax replaces {{ name }} with 'Anna' in the rendered HTML.

3. Final Answer:

   <div>Hello, Anna!</div> -> Option B

4. Quick Check:

   Variable value replaces {{ name }} [OK]

Hint: Mustache {{ }} shows variable value, not the code itself [OK]

Common Mistakes:

• Expecting to see {{ name }} literally
• Confusing variable name with its value
• Leaving interpolation empty

4. What is wrong with this Vue template snippet?

<div>{{ user.name </div>

medium

A. Mustache syntax cannot access object properties.

B. Variable user is not defined.

C. Interpolation must use square brackets instead of curly braces.

D. Missing closing curly braces for interpolation.

Solution

1. Step 1: Check mustache syntax completeness

   The snippet has only one closing curly brace; mustache syntax requires double closing braces }}.

2. Step 2: Confirm correct syntax for interpolation

   Proper interpolation should be {{ user.name }} with both opening and closing double braces.

3. Final Answer:

   Missing closing curly braces for interpolation. -> Option D

4. Quick Check:

   Mustache needs {{ and }} to work [OK]

Hint: Always close mustache with double braces }} [OK]

Common Mistakes:

• Using single closing brace
• Forgetting to close interpolation
• Thinking square brackets are needed

5. You want to display a greeting that changes based on time using mustache syntax. Which template code correctly shows 'Good morning' if hour is less than 12, otherwise 'Good afternoon'?

hard

A. <div>{{ hour < 12 ? 'Good morning' : 'Good afternoon' }}</div>

B. <div>{{ if (hour < 12) 'Good morning' else 'Good afternoon' }}</div>

C. <div>{{ hour < 12 && Good morning || 'Good afternoon' }}</div>

D. <div>{{ hour < 12 ? Good morning : Good afternoon }}</div>

Solution

1. Step 1: Understand mustache supports JavaScript expressions

   Mustache syntax in Vue allows simple JavaScript expressions like ternary operators.

2. Step 2: Check each option for correct syntax

   <div>{{ hour < 12 ? 'Good morning' : 'Good afternoon' }}</div> uses a valid ternary expression with quotes around strings, which is correct. <div>{{ if (hour < 12) 'Good morning' else 'Good afternoon' }}</div> uses invalid syntax inside mustache. <div>{{ hour < 12 && Good morning || 'Good afternoon' }}</div> misses quotes around Good morning, causing a syntax error. <div>{{ hour < 12 ? Good morning : Good afternoon }}</div> misses quotes around strings, causing errors.

3. Final Answer:

   <div>{{ hour < 12 ? 'Good morning' : 'Good afternoon' }}</div> -> Option A

4. Quick Check:

   Ternary with quotes works in mustache [OK]

Hint: Use ternary with quotes inside {{ }} for conditional text [OK]

Common Mistakes:

• Omitting quotes around strings
• Using if-else statements inside mustache
• Using logical operators incorrectly