Check Palindrome - Javascript

JavaScript is a popular programming language, and one of its useful features is its ability to check if a word is a palindrome. A palindrome is a word that can be read the same way backward as forward. For example, "racecar" is a palindrome. This article will explain how to check if a word is a palindrome in JavaScript using a function called checkPalindrome.

Using the checkPalindrome Function

The checkPalindrome functions takes a string as input and returns true if the string is a palindrome, and false otherwise. Here is the implementation of the checkPalindrome function:

function checkPalindrome(str) {
  // convert the string to lowercase and remove non-alphanumeric characters
  let cleanStr = str.toLowerCase().replace(/[^a-z0-9]/g, '');
  // check if the string is equal to its reverse
  return cleanStr === cleanStr.split('').reverse().join('');
}

Explanation of the checkPalindrome Function

The checkPalindrome function takes a string str as input. The first line of the function converts the string to lowercase using the toLowerCase() method. It then uses the replace() method to remove all non-alphanumeric characters from the string by using a regular expression. The regular expression /[^a-z0-9]/g matches all characters that are not lowercase letters or digits, and the g flag makes the replacement global, i.e., it replaces all occurrences of non-alphanumeric characters.

The second line of the function checks if the cleaned-up string is equal to its reverse. To do this, it first converts the string into an array of characters using the split('') method, then reverses the array using the reverse() method, and finally converts the array back into a string using the join('') method. This is a common technique used to reverse a string in JavaScript.

If the cleaned-up string is equal to its reverse, the function returns true, otherwise it returns false.

Example Usage of the checkPalindrome Function

Here are some examples of how to use the checkPalindrome function:

console.log(checkPalindrome('racecar')); // true
console.log(checkPalindrome('A man, a plan, a canal, Panama!')); // true
console.log(checkPalindrome('hello world')); // false

In the first example, the input string "racecar" is a palindrome, so the function returns true. In the second example, the input string "A man, a plan, a canal, Panama!" is also a palindrome, but with some punctuation and capital letters, which are removed by the function. In the third example, the input string "hello world" is not a palindrome, so the function returns false.

Conclusion

The checkPalindrome function is a useful tool for checking if a word is a palindrome in JavaScript. It is based on converting the string to lowercase, removing non-alphanumeric characters, and comparing the cleaned-up string to its reverse. With these techniques, you can easily determine if a given string is a palindrome.