🔍Regex Recipes

Trim Leading/Trailing Whitespace

Remove whitespace from start and end of lines with multiline variations.

Pattern

^\s+|\s+$

Explanation

Matches whitespace at the start (^\s+) or end (\s+$) of string. Use multiline flag for each line.

Examples

Leading spaces

Input

   text

Output

Replace with: text

Trailing spaces

Input

text

Output

Replace with: text

Both sides

Input

  text

Output

Replace with: text

Already trimmed

Input

text

Output

No change

Code Examples

JavaScript

// Single line trim
const text = '  hello world  ';
const trimmed = text.replace(/^\s+|\s+$/g, '');
// Or use built-in: text.trim()

// Trim each line in multiline text
const multiline = `
  line 1  
  line 2  
`;
const trimmedLines = multiline
  .replace(/^\s+|\s+$/gm, '');

Try it Now

Open in Regex Tester Open in Find & Replace

💡 Tips

In JavaScript, use .trim() for simple cases
Add m flag for multiline trimming
Combine with duplicate space removal for full normalization
Consider trimStart() and trimEnd() for one-sided trimming

⚠️ Common Pitfalls

Use multiline flag (m) to trim each line separately
May want to preserve intentional indentation
Built-in trim() is usually better for simple cases
Does not normalize internal whitespace