res.render for templates in Express - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to render the 'home' template using Express.

Express

app.get('/', (req, res) => {
  res.[1]('home');
});

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

Awrite

Bsend

Crender

Djson

Attempts:

3 left

💡 Hint

Common Mistakes

Using res.send instead of res.render

Trying to use res.json to render templates

The res.render method tells Express to render a template file named 'home'.

2fill in blank

medium

Complete the code to pass a variable 'title' with value 'Welcome' to the template.

Express

app.get('/', (req, res) => {
  res.render('home', { [1]: 'Welcome' });
});

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

Atitle

Bmessage

Cname

Dheader

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name not expected by the template

Passing the variable outside the object

The object passed as the second argument to res.render contains variables for the template. Here, title is the variable name.

3fill in blank

hard

Fix the error in the code to correctly render the 'profile' template with user data.

Express

app.get('/profile', (req, res) => {
  const user = { name: 'Alice' };
  res.[1]('profile', { user });
});

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

Asend

Brender

Cjson

Dwrite

Attempts:

3 left

💡 Hint

Common Mistakes

Using res.send instead of res.render

Passing data incorrectly

To render a template with data, use res.render and pass the data as an object.

4fill in blank

hard

Fill both blanks to render 'dashboard' template with a user name and age.

Express

app.get('/dashboard', (req, res) => {
  res.render('dashboard', { [1]: 'Bob', [2]: 30 });
});

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

Ausername

Bage

Cname

DuserAge

Attempts:

3 left

💡 Hint

Common Mistakes

Using inconsistent variable names

Passing values outside the object

The template expects variables named name and age to display user info.

5fill in blank

hard

Fill all three blanks to render 'product' template with id, name, and price variables.

Express

app.get('/product', (req, res) => {
  res.render('product', { [1]: 101, [2]: 'Book', [3]: 9.99 });
});

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

AproductId

Bname

Cprice

Did

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names like productId instead of id

Mixing up variable names and values

The template uses id, name, and price to show product details.

Practice

1. What does res.render do in an Express app?

easy

A. It creates and sends an HTML page using a template and data.

B. It sends a JSON response to the client.

C. It redirects the user to another URL.

D. It logs a message to the server console.

Solution

1. Step 1: Understand the purpose of res.render

   res.render is used to create a web page by combining a template with data.

2. Step 2: Identify what res.render sends to the client

   It sends the generated HTML page as the response to the user's browser.

3. Final Answer:

   It creates and sends an HTML page using a template and data. -> Option A

4. Quick Check:

   res.render = sends HTML page [OK]

Hint: Remember: res.render sends HTML, not JSON or redirects [OK]

Common Mistakes:

• Confusing res.render with res.json
• Thinking res.render redirects the user
• Assuming res.render logs info instead of sending response

2. Which of the following is the correct syntax to render a template named 'home' with a variable 'title' set to 'Welcome'?

easy

A. res.render('home', 'title', 'Welcome');

B. res.render('home', { title: 'Welcome' });

C. res.render('home', ['title', 'Welcome']);

D. res.render('home', title = 'Welcome');

Solution

1. Step 1: Check the method signature of res.render

   It takes the template name as first argument and an object with variables as second argument.

2. Step 2: Match the correct object syntax

   The correct way to pass variables is using an object like { title: 'Welcome' }.

3. Final Answer:

   res.render('home', { title: 'Welcome' }); -> Option B

4. Quick Check:

   res.render(template, object) = correct syntax [OK]

Hint: Pass variables as an object, not as separate arguments [OK]

Common Mistakes:

• Passing variables as separate arguments instead of an object
• Using array instead of object for variables
• Assigning variables inside the argument list incorrectly

3. Given this Express code snippet, what will the user see when visiting '/'?

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

Assuming the 'index' template contains: <h1>Hello, <%= name %>!</h1>

medium

A. Hello, Alice!

B. Hello, <%= name %>!

C. Error: Template not found

D. Hello, !

Solution

1. Step 1: Understand how res.render passes data to template

   The object { name: 'Alice' } provides the value for name in the template.

2. Step 2: Evaluate the template output

   The template uses <%= name %> to insert the value 'Alice' into the HTML.

3. Final Answer:

   <h1>Hello, Alice!</h1> -> Option A

4. Quick Check:

   Template variable replaced correctly =

   Hello, Alice!

   [OK]

Hint: Variables in template replaced by object keys passed to res.render [OK]

Common Mistakes:

• Expecting raw template tags to appear in output
• Assuming missing template causes silent empty output
• Confusing template syntax with HTML escaping

4. What is wrong with this Express code snippet?

app.get('/about', (req, res) => {
  res.render('about', title: 'About Us');
});

medium

A. res.render cannot be used inside app.get routes.

B. The template name 'about' should be a variable, not a string.

C. The second argument to res.render should be an object, but it's missing curly braces.

D. The route path '/about' is invalid.

Solution

1. Step 1: Check the syntax of res.render arguments

   The second argument must be an object with key-value pairs, but here it's written without curly braces.

2. Step 2: Identify the correct object syntax

   It should be { title: 'About Us' } to pass variables properly.

3. Final Answer:

   The second argument to res.render should be an object, but it's missing curly braces. -> Option C

4. Quick Check:

   res.render second argument = object with braces [OK]

Hint: Always wrap variables in an object with curly braces for res.render [OK]

Common Mistakes:

• Omitting curly braces around variables object
• Passing variables as separate arguments
• Misunderstanding route handler usage

5. You want to render a 'profile' template that shows a user's name and age. The user data is in an object user = { name: 'Bob', age: 30 }. Which code correctly renders the template passing the user data so the template can access name and age directly?

hard

A. res.render('profile', ['name', user.name, 'age', user.age]);

B. res.render('profile', { user });

C. res.render('profile', { name: user, age: user.age });

D. res.render('profile', { name: user.name, age: user.age });

Solution

1. Step 1: Understand how template variables are accessed

   The template expects variables name and age directly, not inside a nested object.

2. Step 2: Pass variables as separate keys in an object

   Passing { name: user.name, age: user.age } makes name and age available directly in the template.

3. Final Answer:

   res.render('profile', { name: user.name, age: user.age }); -> Option D

4. Quick Check:

   Pass variables as keys for direct template access [OK]

Hint: Pass each variable separately for direct template use [OK]

Common Mistakes:

• Passing the whole user object instead of separate keys
• Passing variables as an array instead of object
• Assuming template can access nested object keys without dot notation