LEARN JAVASCRIPT
π Boost Your JavaScript Skills: Master Functions with These 10 Practical Exercises! π
Coding EXERCISES explanations!
Exercise: Write a simple JavaScript function to print “Hello, World!”.
function sayHello() {
console.log(“Hello, World!”);
}
sayHello();
Explanation: This exercise demonstrates a basic function declaration in JavaScript. The function sayHello when called, executes the console.log statement to print “Hello, World!”.
Exercise: Create a function that takes two numbers as arguments and returns their sum.
function add(a, b) {
return a + b;
}
console.log(add(2, 3)); // Output: 5
Explanation: The function add takes two parameters and returns their sum. When add(2, 3) is called, it returns 5.
Exercise: Write a function that takes a string as an argument and returns the string in reverse.
function reverseString(str) {
return str.split(”).reverse().join(”);
}
console.log(reverseString(“Hello”)); // Output: “olleH”
Explanation: This function reverses a string by splitting it into an array of characters (split(”)), reversing the array (reverse()), and then joining the characters back into a string (join(”)).
Exercise: Create a function that calculates the factorial of a number.
function factorial(num) {
if (num === 0 || num === 1) {
return 1;
}
return num * factorial(num – 1);
}
console.log(factorial(5)); // Output: 120
Explanation: This is a recursive function that calculates the factorial of a number. The base case returns 1 when num is 0 or 1. Otherwise, it calls itself with num – 1.
Exercise: Write a JavaScript function that checks whether a passed string is a palindrome or not.
function isPalindrome(str) {
return str === str.split(”).reverse().join(”);
}
console.log(isPalindrome(“madam”)); // Output: true
console.log(isPalindrome(“hello”)); // Output: false
Explanation: This function checks if a string is a palindrome by comparing the string with its reversed version. It uses the same string reversal method as in exercise 3.
Exercise: Create a function that removes duplicates from an array.
function removeDuplicates(arr) {
return […new Set(arr)];
}
console.log(removeDuplicates([1, 2, 2, 3])); // Output: [1, 2, 3]
Explanation: This function removes duplicates from an array using the Set object, which only stores unique values, and then converts it back to an array.
Exercise: Write a function to convert Celsius to Fahrenheit.
function celsiusToFahrenheit(celsius) {
return celsius * 9/5 + 32;
}
console.log(celsiusToFahrenheit(0)); // Output: 32
Explanation: The function converts Celsius to Fahrenheit using the formula F = C * 9/5 + 32.
Exercise: Create a function that finds the largest number in an array.
function findLargest(arr) {
return Math.max(…arr);
}
console.log(findLargest([1, 2, 3, 4])); // Output: 4
Explanation: This function finds the largest number in an array using the Math.max() function along with the spread operator to pass all array elements as individual arguments.
Exercise: Write a function that checks if a number is even.
function isEven(num) {
return num % 2 === 0;
}
console.log(isEven(4)); // Output: true
console.log(isEven(5)); // Output: false
Explanation: This function checks if a number is even by using the modulus operator (%). If the number is divisible by 2 with no remainder, it returns true, indicating the number is even.
Exercise: Create a function that takes an array of numbers and returns a new array containing only the positive numbers.
function filterPositiveNumbers(arr) {
return arr.filter(num => num > 0);
}
console.log(filterPositiveNumbers([-1, 2, -3, 4, -5])); // Output: [2, 4]
Explanation: This function uses the filter() method to create a new array with only positive numbers. The filter() method creates a new array with all elements that pass the test implemented by the provided function, in this case, num > 0.
These exercises cover various aspects of JavaScript functions, demonstrating different uses and capabilities of functions in JavaScript, from basic operations to more advanced concepts like recursion and higher-order functions.