Output formatting basics in Javascript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print the message to the console.

Javascript

console.log([1]);

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

Aprint('Hello, world!')

B'Hello, world!'

Cconsole.log('Hello, world!')

DHello, world!

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the text.

Using print() instead of console.log().

To print text in JavaScript, you must put the text inside quotes as a string.

2fill in blank

medium

Complete the code to print the number 42 to the console.

Javascript

console.log([1]);

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

A'42'

Bnumber(42)

C"42"

D42

Attempts:

3 left

💡 Hint

Common Mistakes

Putting numbers inside quotes makes them strings.

Using number() function which is not needed here.

Numbers are printed without quotes in JavaScript.

3fill in blank

hard

Fix the error in the code to print the variable value.

Javascript

let name = 'Alice';
console.log([1]);

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

A"name"

B'name'

Cname

Dconsole.log(name)

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around the variable name.

Writing console.log inside console.log.

To print the value of a variable, use the variable name without quotes.

4fill in blank

hard

Fill both blanks to print a greeting with a variable.

Javascript

let user = 'Bob';
console.log('Hello, ' + [1] + [2]);

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

Auser

B'!'

C'?'

D"!"

Attempts:

3 left

💡 Hint

Common Mistakes

Putting quotes around the variable name.

Using wrong punctuation marks.

Use the variable name and add an exclamation mark as a string.

5fill in blank

hard

Fill all three blanks to print a formatted message using template literals.

Javascript

let age = 30;
let name = 'Carol';
console.log(`My name is [1] and I am [2] years [3].`);

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

A${name}

B${age}

Cold

Dyears

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting ${} around variables.

Using quotes instead of backticks.

Missing the word 'old' in the sentence.

Use ${variable} inside backticks for variables and add the word 'old' to complete the sentence.

Practice

1. What is the correct way to include a variable name inside a string using template literals in JavaScript?

easy

A. console.log(`Hello, ${name}!`);

B. console.log('Hello, ' + name + '!');

C. console.log("Hello, ${name}!");

D. console.log('Hello, ${name}!');

Solution

1. Step 1: Understand template literals syntax

   Template literals use backticks (`) and ${} to insert variables inside strings.

2. Step 2: Identify correct usage

   console.log(`Hello, ${name}!`); uses backticks and ${name} correctly to embed the variable.

3. Final Answer:

   console.log(`Hello, ${name}!`); -> Option A

4. Quick Check:

   Backticks + ${} = correct template literal [OK]

Hint: Use backticks and ${variable} for easy variable insertion [OK]

Common Mistakes:

• Using quotes instead of backticks for template literals
• Forgetting ${} around variable
• Using single or double quotes with ${} which won't interpolate

2. Which of the following is the correct syntax to print the number 5 and the word 'apples' in one line using template literals?

easy

A. console.log(`5 apples`);

B. console.log(`5 + apples`);

C. console.log('5 apples');

D. console.log(`5 ${apples}`);

Solution

1. Step 1: Check the use of template literals

   Backticks allow strings with variables inside ${}, but here no variable is needed.

2. Step 2: Identify correct string

   console.log(`5 apples`); correctly uses backticks with plain text '5 apples'.

3. Final Answer:

   console.log(`5 apples`); -> Option A

4. Quick Check:

   Backticks with plain text = valid string [OK]

Hint: Use backticks for strings even without variables [OK]

Common Mistakes:

• Using quotes instead of backticks when template literals expected
• Trying to insert undefined variable apples
• Adding plus sign inside template literal as text

3. What will be the output of the following code?

const count = 3;
console.log(`You have ${count} new messages.`);

medium

A. You have ${count} new messages.

B. You have count new messages.

C. You have 3 new messages.

D. SyntaxError

Solution

1. Step 1: Understand template literal variable insertion

   The variable count inside ${} is replaced by its value 3.

2. Step 2: Evaluate the console.log output

   The string becomes 'You have 3 new messages.' and prints exactly that.

3. Final Answer:

   You have 3 new messages. -> Option C

4. Quick Check:

   Variable inside ${} = replaced by value [OK]

Hint: Variables inside ${} show their value in template strings [OK]

Common Mistakes:

• Thinking ${count} prints literally
• Confusing quotes and backticks
• Expecting variable name instead of value

4. Find the error in this code snippet:

let user = 'Anna';
console.log('Welcome, ${user}!');

medium

A. Missing semicolon after let declaration

B. Single quotes do not allow variable interpolation

C. Variable user is not declared

D. Backticks are missing around the string

Solution

1. Step 1: Check string quotes for interpolation

   Single quotes ('') do not process ${} as variable placeholders.

2. Step 2: Identify correct string type for template literals

   Backticks (`) are needed to enable variable interpolation.

3. Final Answer:

   Single quotes do not allow variable interpolation -> Option B

4. Quick Check:

   Use backticks for ${} interpolation [OK]

Hint: Use backticks, not single quotes, for ${} variables [OK]

Common Mistakes:

• Thinking single quotes support ${} interpolation
• Ignoring missing backticks
• Assuming variable is undeclared

5. You want to print a message showing a user's name and age using template literals. The variables are name = 'Sam' and age = 25. Which code correctly formats the output as:
Hello, Sam! You are 25 years old.

hard

A. console.log(`Hello, ${name}! You are age years old.`);

B. console.log('Hello, ' + name + '! You are ' + age + ' years old.');

C. console.log(`Hello, name! You are age years old.`);

D. console.log(`Hello, ${name}! You are ${age} years old.`);

Solution

1. Step 1: Use template literals with variables

   Backticks and ${} allow embedding variables name and age inside the string.

2. Step 2: Check each option for correct variable usage

   console.log(`Hello, ${name}! You are ${age} years old.`); correctly uses ${name} and ${age} to insert values.

3. Final Answer:

   console.log(`Hello, ${name}! You are ${age} years old.`); -> Option D

4. Quick Check:

   Backticks + ${var} for each variable = correct [OK]

Hint: Use ${variable} inside backticks for multiple variables [OK]

Common Mistakes:

• Using variable names without ${} inside template literals
• Mixing quotes and backticks incorrectly
• Concatenating strings instead of using template literals