Output formatting basics in Javascript - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this template literal?

Consider the following JavaScript code using template literals. What will be printed to the console?

Javascript

const name = "Alice";
const age = 30;
console.log(`Name: ${name}, Age: ${age}`);

A Name: name, Age: age

B Name: ${name}, Age: ${age}

C Name: Alice Age: 30

D Name: Alice, Age: 30

💡 Hint

Remember that template literals use backticks and ${} to insert variables.

Template literals allow embedding variables inside strings using ${variable}. The output replaces these placeholders with actual values.

❓ Predict Output

intermediate

What does this code print with number formatting?

Look at this code that formats a number to two decimal places. What is the output?

Javascript

const price = 5;
console.log(`Price: $${price.toFixed(2)}`);

A Price: $5

B Price: $5.00

C Price: $5.0

D Price: $5.000

💡 Hint

toFixed(2) formats the number with exactly two decimal places.

The toFixed(2) method converts the number to a string with two digits after the decimal point.

❓ Predict Output

advanced

What is the output of this code using padStart?

This code uses padStart to format a string. What will it print?

Javascript

const id = "42";
console.log(id.padStart(5, '0'));

A 00042

B 42

C 42000

D 43

💡 Hint

padStart adds characters to the start until the string reaches the given length.

padStart(5, '0') adds zeros to the left of '42' until the total length is 5 characters.

❓ Predict Output

advanced

What is the output of this code using Intl.NumberFormat?

This code formats a number as currency. What will it print?

Javascript

const amount = 1234.56;
const formatter = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
console.log(formatter.format(amount));

A USD 1,234.56

B 1234.56 USD

C $1,234.56

D 1,234.56

💡 Hint

Intl.NumberFormat formats numbers according to locale and options.

The formatter formats the number as US dollars with commas and two decimals.

🧠 Conceptual

expert

Which option causes a runtime error when formatting output?

Which of the following code snippets will cause a runtime error when executed?

A console.log(`Result: ${undefinedVariable}`);

B console.log('Value: ' + (10).toFixed(2));

C console.log(`Sum: ${5 + 3}`);

D console.log('Price: $' + (20).toLocaleString('en-US'));

💡 Hint

Check if all variables are defined before using them in output.

Using an undefined variable inside a template literal causes a ReferenceError at runtime.