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How To Trim Whitespace From The Start Or End Of String Using Javascript

When dealing with strings in JavaScript, it is not uncommon to encounter situations where leading or trailing whitespace needs to be removed. Whitespace can include spaces, tabs, line breaks, or any other non-printable characters. Trimming whitespace from the start or end of a string is a common task in data processing, form validation, or manipulating user input. JavaScript provides several methods to accomplish this, allowing you to clean up strings and ensure data integrity.

In this article, we will explore different approaches to removing whitespace from the start or end of a string. We will cover methods such as String.trim(), which is a built-in method specifically designed for this purpose, as well as using regular expressions with String.replace(). We will demonstrate an alternative approach also. By learning these techniques, you will be equipped to efficiently handle whitespace trimming in your JavaScript applications and ensure that your string data is properly formatted.

01. Using "String.trim()"
02. Using "String.replace()" with Regular Expression
03. Using "String.replace()" with "Trim-specific" Regular Expression
04. Using "String.split()" and "Array.join()"

01. Using "String.trim()"

var str = "   Hello, World!   ";
var trimmedStr = str.trim();
console.log(trimmedStr);

Output

"Hello, World!"

The String.trim() method removes whitespace from both the start and end of the string, returning the trimmed version.

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02. Using "String.replace()" with Regular Expression

var str = "   Hello, World!   ";
var trimmedStr = str.replace(/^\s+|\s+$/g, "");
console.log(trimmedStr);

Output

"Hello, World!"

Here, a regular expression (/^\s+|\s+$/g) is used with String.replace() to match and replace leading and trailing whitespace characters with an empty string.

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03. Using "String.replace()" with "Trim-specific" Regular Expression

var str = "   Hello, World!   ";
var trimmedStr = str.replace(/^\s*(.*?)\s*$/, "$1");
console.log(trimmedStr);

Output

"Hello, World!"

In this method, a trim-specific regular expression (/^\s*(.*?)\s*$/) is used with String.replace() to match and capture the non-whitespace characters, effectively removing the leading and trailing whitespace.

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04. Using "String.split()" and "Array.join()"

var str = "   Hello, World!   ";
var trimmedStr = str.split(" ").filter(Boolean).join(" ");
console.log(trimmedStr);

Output

"Hello, World!"

Here, String.split(" ") is used to split the string into an array based on whitespace, Array.filter(Boolean) filters out any empty array elements, and Array.join(" ") concatenates the remaining elements back into a string.

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