JSX in Vue components - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is JSX in the context of Vue components?

JSX is a syntax that lets you write HTML-like code inside JavaScript. In Vue, it allows you to create component templates using JavaScript expressions instead of separate template files.

intermediate

How do you enable JSX support in a Vue 3 project?

You install the @vitejs/plugin-vue-jsx plugin (for Vite) or @vue/babel-plugin-jsx (for Babel) and configure your build tool to use it. This lets Vue understand JSX syntax in your components.

beginner

Show a simple Vue 3 functional component using JSX that renders a button with a click event.

const MyButton = () => {
  return <button onClick={() => alert('Clicked!')}>Click me</button>;
};

This component returns a button element with an onClick event handler using JSX.

beginner

How do you bind dynamic data in JSX inside Vue components?

You use curly braces {} to embed JavaScript expressions. For example,

{message}

will display the value of the message variable inside the div.

intermediate

What is a key difference between Vue templates and JSX in Vue components?

Vue templates use HTML-like syntax with directives (like v-if), while JSX uses JavaScript expressions and functions directly. JSX offers more flexibility but requires understanding JavaScript well.

Which plugin is commonly used to enable JSX in a Vue 3 project with Vite?

A @vue/babel-plugin-jsx

B vue-template-compiler

C vue-loader

D @vitejs/plugin-vue-jsx

The @vitejs/plugin-vue-jsx plugin is designed for Vite to support JSX in Vue 3 projects.

In JSX for Vue, how do you attach a click event to a button?

A <button onClick={handleClick}>

B <button v-on:click={handleClick}>

C <button @click='handleClick'>

D <button click={handleClick}>

In JSX, event handlers use camelCase like onClick with a JavaScript function.

How do you insert a JavaScript variable called 'title' inside JSX?

A <div>{title}</div>

B <div>title</div>

C <div>{{title}}</div>

D <div>$(title)</div>

JSX uses curly braces {} to embed JavaScript expressions inside the markup.

Which of the following is true about JSX in Vue components?

A JSX is the default template syntax in Vue 3.

B JSX replaces the need for JavaScript in Vue components.

C JSX allows writing templates using JavaScript expressions.

D JSX cannot handle events in Vue.

JSX lets you write templates as JavaScript expressions, offering flexibility.

What is a benefit of using JSX over Vue templates?

A Easier for beginners to read and write.

B More flexibility with JavaScript logic inside templates.

C No need to configure build tools.

D Better SEO by default.

JSX allows embedding full JavaScript logic directly, giving more control.

Explain how JSX works inside Vue components and how it differs from Vue templates.

Think about how you write the UI and logic in each approach.

Describe the steps to set up JSX support in a Vue 3 project using Vite.

Focus on the plugin installation and configuration.

Practice

1. What is the main purpose of using JSX in Vue components?

easy

A. To write HTML-like code inside JavaScript functions for UI rendering

B. To replace JavaScript with HTML code

C. To write CSS styles directly inside Vue components

D. To create Vue components without any JavaScript

Solution

1. Step 1: Understand JSX role in Vue

   JSX allows writing HTML-like syntax inside JavaScript, making UI code dynamic and easier to manage.

2. Step 2: Compare options

   Only To write HTML-like code inside JavaScript functions for UI rendering correctly describes JSX's purpose. Others confuse JSX with CSS or removing JavaScript.

3. Final Answer:

   To write HTML-like code inside JavaScript functions for UI rendering -> Option A

4. Quick Check:

   JSX = HTML-like code in JS [OK]

Hint: JSX mixes HTML look inside JavaScript functions [OK]

Common Mistakes:

• Thinking JSX replaces JavaScript entirely
• Confusing JSX with CSS styling
• Believing JSX removes the need for Vue components

2. Which of the following is the correct way to return JSX inside the setup() function in Vue 3?

easy

A. return Hello;

B. return function() { Hello };

C. return () => (Hello);

D. return { template: 'Hello' };

Solution

1. Step 1: Recall Vue 3 setup JSX syntax

   In Vue 3, setup() returns a render function, usually an arrow function returning JSX wrapped in parentheses.

2. Step 2: Evaluate options

   return () => (
   Hello); correctly returns an arrow function with JSX. return

   Hello

   ; returns JSX directly (invalid). return function() {

   Hello

   }; returns a function but misses return statement. return { template: '

   Hello

   ' }; uses template string, not JSX.

3. Final Answer:

   return () => (<div>Hello</div>); -> Option C

4. Quick Check:

   setup returns arrow function with JSX [OK]

Hint: Always return an arrow function wrapping JSX in setup() [OK]

Common Mistakes:

• Returning JSX directly without a function
• Using function without return statement
• Confusing JSX with template strings

3. What will be the rendered output of this Vue JSX component?

import { defineComponent } from 'vue';
export default defineComponent({
  setup() {
    const name = 'Vue';
    return () => (
      

        
Hello, {name}!
      
    );
  }
});

medium

A. Hello, Vue!

B. Hello, {name}!

C. Hello, !

D. SyntaxError due to JSX expression

Solution

1. Step 1: Understand JSX expression interpolation

   In JSX, curly braces insert JavaScript expressions. Here, {name} inserts the string 'Vue'.

2. Step 2: Predict rendered HTML

   The component renders a div with an h1 containing 'Hello, Vue!'. No syntax errors occur.

3. Final Answer:

   <div><h1>Hello, Vue!</h1></div> -> Option A

4. Quick Check:

   JSX {name} inserts variable value [OK]

Hint: JSX curly braces insert JavaScript values directly [OK]

Common Mistakes:

• Thinking JSX shows variable name literally
• Expecting empty output if variable used
• Assuming JSX causes syntax errors without Babel

4. Identify the error in this Vue JSX component code:

import { defineComponent } from 'vue';
export default defineComponent({
  setup() {
    const count = 0;
    return () => {
      {count}
    };
  }
});

medium

A. count variable should be reactive

B. JSX cannot be used inside setup()

C. setup() should not return a function

D. Missing parentheses around JSX in return function

Solution

1. Step 1: Check JSX return syntax in arrow function

   The arrow function uses curly braces but does not return JSX explicitly or wrap JSX in parentheses, causing no output.

2. Step 2: Correct syntax for returning JSX

   JSX must be wrapped in parentheses and returned explicitly, e.g., () => ( <button>{count}</button> ).

3. Final Answer:

   Missing parentheses around JSX in return function -> Option D

4. Quick Check:

   JSX must be wrapped in parentheses and returned [OK]

Hint: Wrap JSX in parentheses when returning from arrow function [OK]

Common Mistakes:

• Forgetting to return JSX explicitly
• Not wrapping JSX in parentheses
• Thinking reactive is required for static display

5. You want to create a Vue JSX component that renders a list of items passed as a prop. Which is the correct way to map the items array to JSX elements inside setup()?

hard

A. return () => ({props.items.forEach(item => {item})});

B. return () => ({props.items.map(item => {item})});

C. return () => ({for (const item of props.items) {item}});

D. return () => ({props.items.map(item => '' + item + '')});

Solution

1. Step 1: Understand how to render lists in JSX

   JSX uses JavaScript expressions. map() returns an array of JSX elements, perfect for rendering lists.

2. Step 2: Evaluate each option

   return () => (
   {props.items.map(item =>
   • {item}
   )}
   ); correctly uses map() to return
3. elements. return () => (
   {props.items.forEach(item =>
   • {item}
   )}
   ); uses forEach which returns undefined. return () => (
   {for (const item of props.items)
   • {item}
   }
   ); uses invalid syntax inside JSX. return () => (
   {props.items.map(item => '
   • ' + item + '
   ')}
   ); returns strings, not JSX elements.

4. Final Answer:

   return () => (<ul>{props.items.map(item => <li>{item}</li>)}); -> Option B

5. Quick Check:

   Use map() to return JSX list items [OK]

Hint: Use map() to create JSX elements for lists [OK]

Common Mistakes:

• Using forEach instead of map for JSX lists
• Trying to use for loops inside JSX expressions
• Returning strings instead of JSX elements