Output using console.log in Javascript - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of console.log with template literals

What is the output of this code?

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

Javascript

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

A Name: Alice Age: 30

B Name: name, Age: age

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

D Name: Alice, Age: 30

💡 Hint

Look how template literals use ${} to insert variables inside backticks.

The template literal replaces ${name} and ${age} with their variable values inside the string.

❓ Predict Output

intermediate

Output of console.log with multiple arguments

What will this code print?

console.log("Hello", "World", 2024);

Javascript

console.log("Hello", "World", 2024);

A Hello World 2024

B Hello, World, 2024

C HelloWorld2024

D "Hello World 2024"

💡 Hint

console.log prints each argument separated by spaces.

console.log prints all arguments separated by spaces without quotes.

❓ Predict Output

advanced

Output of console.log with undefined variable

What happens when you run this code?

let x;
console.log(x);

Javascript

let x;
console.log(x);

A 0

B null

C undefined

D ReferenceError

💡 Hint

Variables declared but not assigned have a special value.

A declared variable without a value is undefined in JavaScript.

❓ Predict Output

advanced

Output of console.log with object and array

What will this code print?

const obj = {a: 1, b: 2};
const arr = [3, 4];
console.log(obj, arr);

Javascript

const obj = {a: 1, b: 2};
const arr = [3, 4];
console.log(obj, arr);

A { a: 1, b: 2 } [ 3, 4 ]

B [object Object] [3,4]

C {a:1,b:2},[3,4]

D a:1,b:2 3,4

💡 Hint

console.log prints objects and arrays in readable form separated by spaces.

console.log prints the object and array as their readable forms separated by space.

🧠 Conceptual

expert

Behavior of console.log with asynchronous code

What is the output order of this code?

console.log('Start');
setTimeout(() => console.log('Timeout'), 0);
console.log('End');

Javascript

console.log('Start');
setTimeout(() => console.log('Timeout'), 0);
console.log('End');

A End\nStart\nTimeout

B Start\nEnd\nTimeout

C Timeout\nStart\nEnd

D Start\nTimeout\nEnd

💡 Hint

setTimeout with 0 delay runs after current code finishes.

The synchronous logs run first, then the setTimeout callback runs after the current call stack is empty.