Validate UK number

UK-number-validation.js

export function isValidUKPhone(phone: string) {
  const re = /^(\+44\d{10}\b)/;
  return re.test(phone);
}

 describe('isValidUKPhone', () => {
    it('should return true as valid number', () => {
      const phone = '+447473222885';
      expect(isValidUKPhone(phone)).toBeTruthy();
    });

    it('should return false for too long number', () => {
      const phone = '+4474732228852';
      expect(isValidUKPhone(phone)).toBeFalsy();
    });

    it('should return false for other prefix than +44', () => {
      const phone = '+407473222885';
      expect(isValidUKPhone(phone)).toBeFalsy();
    });

    it('should return false for missing +', () => {
      const phone = '447473222885';
      expect(isValidUKPhone(phone)).toBeFalsy();
    });
  });