How do I test this regex in JavaScript and TypeScript?

Use regex.test(): const regex = /^\s+|\s+$/g; const isValid = regex.test(inputString);

What is an example of a matching and non-matching string?

A valid matching string is " untrimmed developer input ". A non-matching string is "clean input".

Is this regex safe from ReDoS (Catastrophic Backtracking)?

Yes, this pattern is optimized for linear execution time and safe for browser-side validation without locking up the UI thread.

HomeRegex LibraryLeading & Trailing Whitespace Regex

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Leading & Trailing Whitespace Regex

Targets superfluous leading and trailing spaces or tab characters across string lines for clean sanitization.

Regular Expression Pattern:

/^\s+|\s+$/g

Valid Match Example:

untrimmed developer input

Invalid / Non-Match Example:

clean input

Regex Syntax Breakdown & Explanation

•^\s+ : Matches spaces at beginning of line
•| : Logical OR operator
•\s+$ : Matches trailing whitespace before end of line

Implementation in Popular Languages

JavaScript / TypeScript

const regex = /^\s+|\s+$/g;
const isValid = regex.test("   untrimmed developer input   ");
console.log(isValid); // true

Python (re)

import re

pattern = r"^\s+|\s+$"
match = re.match(pattern, "   untrimmed developer input   ")
print(bool(match)) # True

Go (regexp)

package main
import (
  "fmt"
  "regexp"
)

func main() {
  re := regexp.MustCompile(`^\s+|\s+$`)
  fmt.Println(re.MatchString("   untrimmed developer input   "))
}

Frequently Asked Questions

Everything you need to know regarding specifications, syntax, and security best practices.

The regular expression pattern is /^\s+|\s+$/g. Targets superfluous leading and trailing spaces or tab characters across string lines for clean sanitization.