How do I test this regex in JavaScript and TypeScript?

Use regex.test(): const regex = /^\+[1-9]\d{1,14}$/; const isValid = regex.test(inputString);

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

A valid matching string is "+14155552671". A non-matching string is "05321234567".

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.

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International E.164 Phone Number Regex

Strict ITU-T E.164 international phone number format beginning with plus sign followed by 2 to 15 digits.

Regular Expression Pattern:

/^\+[1-9]\d{1,14}$/

Valid Match Example:

+14155552671

Invalid / Non-Match Example:

05321234567

Regex Syntax Breakdown & Explanation

•^\+ : Requires leading plus symbol for country calling code
•[1-9] : Leading country code digit cannot be zero
•\d{1,14}$ : Accommodates up to 14 subscriber digits according to ITU standard

Implementation in Popular Languages

JavaScript / TypeScript

const regex = /^\+[1-9]\d{1,14}$/;
const isValid = regex.test("+14155552671");
console.log(isValid); // true

Python (re)

import re

pattern = r"^\+[1-9]\d{1,14}$"
match = re.match(pattern, "+14155552671")
print(bool(match)) # True

Go (regexp)

package main
import (
  "fmt"
  "regexp"
)

func main() {
  re := regexp.MustCompile(`^\+[1-9]\d{1,14}$`)
  fmt.Println(re.MatchString("+14155552671"))
}

Frequently Asked Questions

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

The regular expression pattern is /^\+[1-9]\d{1,14}$/. Strict ITU-T E.164 international phone number format beginning with plus sign followed by 2 to 15 digits.