Setting up TypeScript in Vue project - Try It Yourself

Setting up TypeScript in Vue project

📖 Scenario: You are starting a new Vue 3 project and want to use TypeScript to write safer and clearer code. This project will guide you step-by-step to set up TypeScript in your Vue project using the Composition API.

🎯 Goal: By the end, you will have a Vue 3 component written in TypeScript with a reactive variable and a method, ready to be used in your app.

📋 What You'll Learn

Create a Vue 3 component file with TypeScript support

Define a reactive variable using ref from Vue's Composition API

Add a TypeScript type annotation for the reactive variable

Write a method that updates the reactive variable

Use the reactive variable in the template with proper binding

💡 Why This Matters

🌍 Real World

Using TypeScript in Vue projects helps catch errors early and makes your code easier to understand and maintain.

💼 Career

Many companies use Vue with TypeScript for building scalable and robust web applications, so knowing this setup is valuable for frontend developer roles.

1

Create a Vue component with TypeScript setup

Create a Vue 3 component file named Counter.vue with a <script setup lang="ts"> block and an empty <template> block.

Vue

// Your code here



  

Hint

Use <script setup lang="ts"> to enable TypeScript in your Vue component.

2

Add a reactive variable with TypeScript type

Inside the <script setup lang="ts"> block, import ref from vue and create a reactive variable called count with type number initialized to 0.

Vue

// Import ref from vue
// Create a reactive variable count of type number initialized to 0
// Your code here



  

Hint

Use ref<number>(0) to create a reactive number variable.

3

Add a method to update the reactive variable

Inside the <script setup lang="ts"> block, create a function called increment that increases the value of count by 1.

Vue

import { ref } from 'vue'

const count = ref(0)

// Create a function increment that adds 1 to count.value
// Your code here



  

Hint

Remember to update the reactive variable's value using count.value.

4

Bind the reactive variable and method in the template

In the <template> block, display the current count value inside a <span> and add a <button> that calls the increment function when clicked.

Vue

import { ref } from 'vue'

const count = ref(0)

function increment() {
  count.value++
}



  
  

Hint

Use {{ count }} to show the value and @click="increment" on the button.

Practice

1. What is the main benefit of using TypeScript in a Vue project?

easy

A. It helps catch errors early and improves code clarity.

B. It automatically styles your components.

C. It replaces Vue's template syntax with HTML.

D. It removes the need for JavaScript entirely.

Solution

1. Step 1: Understand TypeScript's role

   TypeScript adds static typing to JavaScript, helping catch errors before running code.

2. Step 2: Relate to Vue projects

   Using TypeScript in Vue improves code clarity and reduces runtime bugs.

3. Final Answer:

   It helps catch errors early and improves code clarity. -> Option A

4. Quick Check:

   TypeScript improves code safety = A [OK]

Hint: TypeScript catches errors before running code [OK]

Common Mistakes:

• Thinking TypeScript styles components
• Confusing TypeScript with HTML templates
• Believing TypeScript removes JavaScript

2. Which command is used to create a new Vue project with TypeScript support?

easy

A. vue create project --typescript

B. npm create vue@latest and select TypeScript option

C. npm install vue typescript

D. vue add typescript

Solution

1. Step 1: Identify the official Vue CLI command

   The recommended way is using npm create vue@latest to start a new project.

2. Step 2: Select TypeScript during setup

   During the interactive setup, you choose TypeScript to enable it.

3. Final Answer:

   npm create vue@latest and select TypeScript option -> Option B

4. Quick Check:

   Use npm create vue@latest for new Vue projects [OK]

Hint: Use npm create vue@latest and pick TypeScript [OK]

Common Mistakes:

• Using old vue CLI commands
• Trying to install TypeScript separately after project creation
• Confusing add commands with create commands

3. Given this Vue component script tag, what is missing to enable TypeScript?

<script>
export default {
  data() {
    return { count: 0 }
  }
}
</script>

medium

A. Wrap the export in a defineComponent call

B. Change data() to setup()

C. Add type="module" to the <script> tag

D. Add lang="ts" attribute to the <script> tag

Solution

1. Step 1: Identify how to enable TypeScript in Vue scripts

   Vue requires lang="ts" on the <script> tag to treat it as TypeScript.

2. Step 2: Check other options

   Changing to setup() or adding type="module" does not enable TypeScript automatically.

3. Final Answer:

   Add lang="ts" attribute to the <script> tag -> Option D

4. Quick Check:

   Use lang="ts" to enable TypeScript [OK]

Hint: Add lang="ts" to script tag for TypeScript [OK]

Common Mistakes:

• Forgetting lang="ts" on script tag
• Confusing setup() with TypeScript enabling
• Assuming type="module" enables TypeScript

4. You added lang="ts" to your Vue component but get errors about missing types. What is the likely cause?

medium

A. You forgot to create or configure tsconfig.json in the project root.

B. You need to remove lang="ts" to fix errors.

C. Vue does not support TypeScript in single file components.

D. You must rename the file extension to .ts instead of .vue.

Solution

1. Step 1: Understand TypeScript configuration needs

   TypeScript requires a tsconfig.json file to know how to compile and check types.

2. Step 2: Check other options

   Removing lang="ts" disables TypeScript, Vue supports TypeScript in .vue files, and renaming files is not needed.

3. Final Answer:

   You forgot to create or configure tsconfig.json in the project root. -> Option A

4. Quick Check:

   tsconfig.json is required for TypeScript setup [OK]

Hint: Create tsconfig.json to avoid missing type errors [OK]

Common Mistakes:

• Removing lang="ts" instead of fixing config
• Thinking Vue disallows TypeScript in .vue files
• Renaming .vue files to .ts incorrectly

5. You want to use TypeScript in a Vue 3 project with the Composition API. Which setup is correct for the script block?

hard

A. <script lang="js" setup>
import { ref } from 'vue'
const count = ref(0)
</script>

B. <script>
import { ref } from 'vue'
const count = ref(0)
</script>

C. <script lang="ts" setup>
import { ref } from 'vue'
const count = ref(0)
</script>

D. <script lang="ts">
export default {
data() { return { count: 0 } }
}
</script>

Solution

1. Step 1: Identify TypeScript and Composition API usage

   Using lang="ts" setup enables TypeScript and Composition API syntax in Vue 3.

2. Step 2: Check other options

   The version with lang="js" setup uses JavaScript not TypeScript, the plain <script> lacks the lang="ts" attribute, and the one using export default with data() is Options API, not Composition API.

3. Final Answer:

   <script lang="ts" setup> with ref import and usage -> Option C

4. Quick Check:

   Use lang="ts" setup for Composition API with TypeScript [OK]

Hint: Use

Common Mistakes:

• Omitting lang="ts" for TypeScript
• Using lang="js" instead of lang="ts"
• Mixing Options API with Composition API syntax