isValidPhoneNumber
Validates if a string is a plausible phone number. Accepts digits, optional + at the beginning, spaces, dashes, and parentheses.
Note: This is not a full validation based on the E.164 or ISO standards — it's a flexible basic format check. If strict compliance is required, consider using a dedicated library such as libphonenumber-js.
1/**
2 * Validates if a string is a plausible phone number.
3 * Accepts digits, optional + at the beginning, spaces, dashes, and parentheses.
4 *
5 * @param str - The phone number string to validate.
6 * @returns True if the input is a valid phone number, false otherwise.
7 */
8export function isValidPhoneNumber(str: string): boolean {
9 return /^\+?[0-9\s\-().]{7,20}$/.test(str.trim());
10}Flexible Format Recognition
Supports a wide range of common phone number formats including spaces, dashes, parentheses, and an optional leading
+.No External Dependencies
Pure regex-based validation keeps the utility lightweight and easily portable across projects.
Trim-Safe
Automatically ignores leading/trailing whitespace before validation, ensuring consistent results.
Length-Based Sanity Check
Enforces a sensible character count (7–20), helping filter out overly short or excessively long inputs.
Tests | Examples
1test('isValidPhoneNumber - valid international and local formats', () => {
2 expect(isValidPhoneNumber('+1 234 567 8900')).toBe(true);
3 expect(isValidPhoneNumber('(123) 456-7890')).toBe(true);
4 expect(isValidPhoneNumber('123-456-7890')).toBe(true);
5 expect(isValidPhoneNumber('1234567890')).toBe(true);
6});
7
8test('isValidPhoneNumber - invalid cases', () => {
9 expect(isValidPhoneNumber('')).toBe(false);
10 expect(isValidPhoneNumber('abc123')).toBe(false);
11 expect(isValidPhoneNumber('12345')).toBe(false); // too short
12 expect(isValidPhoneNumber('+1-800-FLOWERS')).toBe(false); // contains letters
13});Common Use Cases
Form Input Validation
Validate phone numbers submitted by users during sign-up or checkout.
Contact Info Preprocessing
Check plausibility before formatting or storing phone numbers in databases.
CRM or Lead Import
Clean and validate raw phone number strings when importing customer or lead data.
Client-Side Filtering
Prevent users from submitting clearly invalid numbers before backend validation.