Template engine concept in Express - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set EJS as the template engine in Express.

Express

app.set('view engine', '[1]');

Drag options to blanks, or click blank then click option'

Aejs

Bhtml

Ccss

Djs

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'html' or 'js' instead of 'ejs' as the engine name.

Forgetting to set the view engine before rendering.

Express uses app.set('view engine', 'ejs') to specify EJS as the template engine.

2fill in blank

medium

Complete the code to render the 'index' template with Express.

Express

res.[1]('index');

Drag options to blanks, or click blank then click option'

Ajson

Bsend

Cwrite

Drender

Attempts:

3 left

💡 Hint

Common Mistakes

Using res.send instead of res.render for templates.

Trying to use res.json for rendering HTML templates.

Use res.render('index') to render a template named 'index'.

3fill in blank

hard

Fix the error in the code to pass data to the template.

Express

res.render('profile', [1]);

Drag options to blanks, or click blank then click option'

A{name: 'Alice'}

B['name', 'Alice']

C'name=Alice'

Dname: 'Alice'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing an array instead of an object.

Passing a string instead of an object.

Omitting the curly braces around the data.

Data passed to templates must be an object, like {name: 'Alice'}.

4fill in blank

hard

Fill both blanks to correctly set the views folder and render a template.

Express

app.set('[1]', path.join(__dirname, '[2]'));
res.render('home');

Drag options to blanks, or click blank then click option'

Aviews

Btemplates

Cpublic

Dassets

Attempts:

3 left

💡 Hint

Common Mistakes

Setting the views folder to 'public' or 'assets' which are for static files.

Using wrong setting name instead of 'views'.

Express looks for templates in the folder set by app.set('views', ...). Commonly, this is set to a folder like 'templates'.

5fill in blank

hard

Fill all three blanks to pass user data and render the 'dashboard' template.

Express

const user = {name: '[1]', age: [2];
res.[3]('dashboard', {user});

Drag options to blanks, or click blank then click option'

ABob

B30

Crender

Dsend

Attempts:

3 left

💡 Hint

Common Mistakes

Using res.send instead of res.render.

Putting quotes around the number age.

Not passing user data as an object.

Pass user data as an object and use res.render to show the 'dashboard' template.

Practice

1. What is the main purpose of using a template engine in Express?

easy

A. To improve server performance by caching files

B. To combine HTML with data and create dynamic web pages

C. To handle database connections automatically

D. To replace JavaScript code in the backend

Solution

1. Step 1: Understand what template engines do

   Template engines allow mixing HTML with data to generate dynamic content.

2. Step 2: Identify the main purpose in Express

   Express uses template engines to render HTML pages with data, making pages dynamic.

3. Final Answer:

   To combine HTML with data and create dynamic web pages -> Option B

4. Quick Check:

   Template engine purpose = dynamic HTML generation [OK]

Hint: Template engines create HTML pages with data dynamically [OK]

Common Mistakes:

• Thinking template engines handle databases
• Confusing template engines with performance tools
• Believing template engines replace backend code

2. Which Express method is used to render a template with data?

easy

A. res.render()

B. res.sendFile()

C. res.json()

D. res.redirect()

Solution

1. Step 1: Recall Express response methods

   Express has methods like res.sendFile, res.json, res.redirect, and res.render.

2. Step 2: Identify the method for templates

   res.render() is specifically used to render templates with data.

3. Final Answer:

   res.render() -> Option A

4. Quick Check:

   Render templates = res.render() [OK]

Hint: Use res.render() to send templates with data [OK]

Common Mistakes:

• Using res.sendFile() for templates
• Confusing res.json() with rendering HTML
• Trying to use res.redirect() to show templates

3. Given this Express code snippet, what will be the rendered output if the template shows <h1>Hello, <%= name %></h1> and res.render('greet', { name: 'Sam' }) is called?

medium

A. Hello,

B. Hello, <%= name %>

C. Hello, Sam

D. Error: Template variable not found

Solution

1. Step 1: Understand template variable usage

   The template uses <%= name %> to insert the value of 'name'.

2. Step 2: Check the data passed to the template

   The code passes { name: 'Sam' }, so 'Sam' replaces <%= name %>.

3. Final Answer:

   <h1>Hello, Sam</h1> -> Option C

4. Quick Check:

   Template variable replaced by 'Sam' [OK]

Hint: Variables in templates show passed data values [OK]

Common Mistakes:

• Thinking template tags show as text
• Assuming missing variables cause errors
• Ignoring passed data object

4. What is the error in this Express code snippet for rendering a template?

app.get('/hello', (req, res) => {
  res.render('hello', name: 'Alex');
});

medium

A. Template name should be a variable, not a string

B. The route path '/hello' is invalid

C. res.render() cannot be used inside app.get()

D. Missing curly braces around data object in res.render()

Solution

1. Step 1: Check res.render() syntax

   res.render() expects the template name and a data object in curly braces.

2. Step 2: Identify the mistake in data argument

   The code passes name: 'Alex' without curly braces, which is invalid syntax.

3. Final Answer:

   Missing curly braces around data object in res.render() -> Option D

4. Quick Check:

   Data object must be wrapped in {} [OK]

Hint: Always wrap data in {} when passing to res.render() [OK]

Common Mistakes:

• Omitting curly braces for data object
• Thinking template name must be variable
• Believing res.render() can't be used in routes

5. You want to create a page that shows a list of users using a template engine in Express. Which approach correctly passes the user list to the template for rendering?

hard

A. res.render('users', { users: ['Anna', 'Ben', 'Cara'] });

B. res.render('users', ['Anna', 'Ben', 'Cara']);

C. res.render('users', users = ['Anna', 'Ben', 'Cara']);

D. res.render('users', { 'Anna', 'Ben', 'Cara' });

Solution

1. Step 1: Understand how to pass data to templates

   Data must be passed as an object with keys matching template variables.

2. Step 2: Check each option's syntax

   res.render('users', { users: ['Anna', 'Ben', 'Cara'] }); correctly passes an object with key 'users' and an array value.

3. Final Answer:

   res.render('users', { users: ['Anna', 'Ben', 'Cara'] }); -> Option A

4. Quick Check:

   Pass data as object with keys [OK]

Hint: Pass data as an object with named keys to res.render() [OK]

Common Mistakes:

• Passing array directly without object
• Using assignment inside res.render()
• Using invalid object syntax