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Capitalize a word and replace spaces with underscore - JavaScript?
In JavaScript, you can capitalize words and replace spaces with underscores using various string methods. This transformation is commonly needed for creating identifiers, constants, or formatted text.
let input = "tutorials point";
console.log("Input:", input);
// Expected output: "Tutorials_Point"
Input: tutorials point
Let's explore different methods to achieve this transformation in JavaScript.
Using replace() Method
The replace() method searches for a specified pattern in a string and replaces it with a new value. It accepts regular expressions for complex pattern matching.
Syntax
string.replace(searchValue, newValue)
Example 1: Basic Approach
<!DOCTYPE html>
<html>
<body>
<script>
let text = 'welcome to the tutorials point';
// Split, capitalize first letter of each word, join with underscore
let result = text.split(' ')
.map(word => word.charAt(0).toUpperCase() + word.slice(1))
.join('_');
document.write(result);
</script>
</body>
</html>
When executed, this code capitalizes the first letter of each word and replaces spaces with underscores.
Example 2: Using Regular Expression
<!DOCTYPE html>
<html>
<body>
<script>
let sentence = "my favorite subject is javascript";
// Replace spaces with underscores, then capitalize first letter of each word
let result = sentence.replace(/ /g, '_')
.replace(/\b\w/g, function(match) {
return match.toUpperCase();
});
document.write(result);
</script>
</body>
</html>
This approach uses regular expressions to first replace spaces with underscores, then capitalize the first letter of each word.
Using split() Method
The split() method divides a string into an array of substrings based on a specified separator, allowing you to process each word individually.
Syntax
string.split(separator, limit)
Example
<!DOCTYPE html>
<html>
<body>
<script>
function capitalizeAndUnderscore(str) {
let words = str.split(' ');
for (let i = 0; i < words.length; i++) {
words[i] = words[i].charAt(0).toUpperCase() + words[i].slice(1).toLowerCase();
}
return words.join('_');
}
let result = capitalizeAndUnderscore('the best e-learning platform');
document.write(result);
</script>
</body>
</html>
This function splits the string into words, capitalizes the first letter of each word while making the rest lowercase, then joins them with underscores.
Comparison
| Method | Complexity | Readability | Performance |
|---|---|---|---|
| replace() with regex | Medium | Low | Good |
| split() and map() | Low | High | Good |
| split() with loop | Low | Medium | Best |
Conclusion
The split() method combined with map() provides the most readable solution for capitalizing words and replacing spaces with underscores. Choose the approach that best fits your coding style and performance requirements.
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