How to check if a string is a palindrome in JavaScript
Łukasz Holeczek
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Checking if strings are palindromes is useful for word games, text validation, algorithm challenges, and implementing features like password pattern detection or linguistic analysis in JavaScript applications. With over 25 years of experience in software development and as the creator of CoreUI, I’ve implemented palindrome checking in components like form validators, game logic, and text analyzers where detecting symmetric text patterns enhances functionality and user engagement. From my extensive expertise, the most intuitive and readable solution is comparing the string with its reversed version after normalizing the text. This approach is clear, handles case sensitivity and spaces appropriately, and provides reliable palindrome detection.
Use string reversal and comparison to check if a string is a palindrome.
const text = 'racecar'
const cleaned = text.toLowerCase().replace(/[^a-z0-9]/g, '')
const isPalindrome = cleaned === cleaned.split('').reverse().join('')
// Result: true
This method first normalizes the string by converting to lowercase and removing non-alphanumeric characters to handle cases like “A man, a plan, a canal: Panama”. Then it compares the cleaned string with its reversed version created by splitting into characters, reversing the array, and joining back. In this example, ‘racecar’ remains ‘racecar’ when reversed, so the comparison returns true. The cleaning step ensures that spaces, punctuation, and capitalization don’t affect the palindrome check, focusing only on the meaningful character sequence.
Best Practice Note:
This is the same approach we use in CoreUI components for implementing text games, validation rules, and educational features across our component library.
For a more efficient solution with large strings, use two-pointer comparison from both ends: check characters from start and end moving inward. For simple cases without special characters, just use: text.toLowerCase() === text.toLowerCase().split('').reverse().join(''). The normalization step is crucial for real-world palindrome detection.
