JavaScript practice exercises for beginners

Boost your JavaScript skills with beginner-friendly practice exercises! This collection of JavaScript practice exercises covers variables, functions, conditional statements, arrays, loops, and objects.

From simple tasks like printing strings to more advanced challenges like calculating factorials or finding the longest word, these exercises will help you gain hands-on experience and strengthen your understanding of JavaScript. Whether you’re new to programming or looking to reinforce your skills, these exercises provide a perfect opportunity to practice and grow as a JavaScript developer.

1. Hello, World!: Write a script that prints “Hello, World!” to the console.

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

2. Sum of Two Numbers: Write a function that takes two numbers as parameters and returns their sum.

function sumNumbers(a, b) {
  return a + b;
}

console.log(sumNumbers(3, 5)); //8

3. Even or Odd: Write a function that takes a number as a parameter and returns whether it’s even or odd.

function checkEvenOrOdd(number) {
  if (number % 2 === 0) {
    return "Even";
  } else {
    return "Odd";
  }
}

console.log(checkEvenOrOdd(7)); // Odd

4. Reverse a String: Write a function that takes a string as a parameter and returns the reverse of that string.

function reverseString(str) {
  return str.split("").reverse().join("");
}

console.log(reverseString("Hello"));

5. FizzBuzz: Write a program that prints the numbers from 1 to 100. But for multiples of three, print “Fizz” instead of the number, and for the multiples of five, print “Buzz”. For numbers that are multiples of both three and five, print “FizzBuzz”.

for (let i = 1; i <= 100; i++) {
  if (i % 3 === 0 && i % 5 === 0) {
    console.log("FizzBuzz");
  } else if (i % 3 === 0) {
    console.log("Fizz");
  } else if (i % 5 === 0) {
    console.log("Buzz");
  } else {
    console.log(i);
  }
}

6. Find the Largest Number: Write a function that takes an array of numbers as a parameter and returns the largest number in the array.

function findLargestNumber(numbers) {
  let largest = numbers[0];

  for (let i = 1; i < numbers.length; i++) {
    if (numbers[i] > largest) {
      largest = numbers[i];
    }
  }

  return largest;
}

console.log(findLargestNumber([5, 2, 9, 1, 7]));

7. Factorial: Write a function that takes a number as a parameter and returns its factorial.

function factorial(number) {
  if (number === 0 || number === 1) {
    return 1;
  }

  let result = 1;
  for (let i = 2; i <= number; i++) {
    result *= i;
  }

  return result;
}

console.log(factorial(5));

8. Palindrome: Write a function that takes a string as a parameter and returns whether it’s a palindrome (reads the same forward and backward).

function isPalindrome(str) {
  const reversed = str.split("").reverse().join("");
  return str === reversed;
}

console.log(isPalindrome("madam"));

9. Fibonacci Sequence: Write a function that takes the number n as a parameter and prints the first n numbers in the Fibonacci sequence.

function fibonacciSequence(n) {
  const sequence = [0, 1];

  for (let i = 2; i < n; i++) {
    const nextNumber = sequence[i - 1] + sequence[i - 2];
    sequence.push(nextNumber);
  }

  return sequence;
}

console.log(fibonacciSequence(10));

10. Find the Longest Word: Write a function that takes a sentence as a parameter and returns the longest word in the sentence.

function findLongestWord(sentence) {
  const words = sentence.split(" ");
  let longestWord = words[0];

  for (let i = 1; i < words.length; i++) {
    if (words[i].length > longestWord.length) {
      longestWord = words[i];
    }
  }

  return longestWord;
}

console.log(findLongestWord("The quick brown fox jumps over the lazy dog"));