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How to count a number of words in given string in JavaScript?

Javascript Object Oriented Programming Programming

Counting words in a JavaScript string requires handling various whitespace scenarios like multiple spaces, leading/trailing spaces, and newlines. Using regular expressions provides an effective solution.

The Challenge

Strings can contain irregular spacing that affects word counting:

Leading and trailing spaces
Multiple consecutive spaces between words
Newlines with spaces
Empty strings

Step-by-Step Approach

Step 1: Remove Leading and Trailing Spaces

Use regex to eliminate spaces at the start and end of the string:

str.replace(/(^\s*)|(\s*$)/gi, "");

Step 2: Reduce Multiple Spaces to Single Space

Replace consecutive spaces with a single space:

str.replace(/[ ]{2,}/gi, " ");

Step 3: Handle Newlines with Spaces

Remove spaces after newline characters:

str.replace(/<br> /g, "<br>");

Complete Word Counting Function

<html>
<body>
    <script>
        function countWords(str) {
            // Handle empty or whitespace-only strings
            if (!str || str.trim().length === 0) {
                return 0;
            }
            
            // Remove leading and trailing spaces
            str = str.replace(/(^\s*)|(\s*$)/gi, "");
            
            // Replace multiple spaces with single space
            str = str.replace(/[ ]{2,}/gi, " ");
            
            // Handle newlines with spaces
            str = str.replace(/<br> /g, "<br>");
            
            // Split by space and count
            return str.split(' ').length;
        }
        
        // Test examples
        document.write("Example 1: " + countWords("  Tutorix is one of the best E-learning   platforms") + "<br>");
        document.write("Example 2: " + countWords("Hello    world   JavaScript") + "<br>");
        document.write("Example 3: " + countWords("   ") + "<br>");
        document.write("Example 4: " + countWords("Single"));
    </script>
</body>
</html>

Example 1: 8
Example 2: 3
Example 3: 0
Example 4: 1

Alternative Modern Approach

Using trim() and match() provides a cleaner solution:

<html>
<body>
    <script>
        function countWordsModern(str) {
            if (!str || str.trim().length === 0) {
                return 0;
            }
            
            // Match word sequences (non-whitespace characters)
            const words = str.trim().match(/\S+/g);
            return words ? words.length : 0;
        }
        
        document.write("Modern approach: " + countWordsModern("  Hello   world   JavaScript  "));
    </script>
</body>
</html>

Modern approach: 3

Comparison

Method	Handles Empty Strings	Code Length	Readability
Multi-step Regex	With additional check	Longer	More explicit
trim() + match()	Built-in	Shorter	More concise

Conclusion

Both approaches effectively count words by handling whitespace irregularities. The modern trim() and match() method offers cleaner, more maintainable code for most use cases.

vineeth.mariserla

Updated on: 2026-03-15T23:18:59+05:30

5K+ Views

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