Regular expression for validating 'sms' uri scheme. (RFC 5724)[https://tools.ietf.org/html/rfc5724]

Regex for SMS URI (RFC-5724)

This protocol is well-defined by [RFC 5724][1] with the formal definition:

      sms-uri        = scheme ":" sms-hier-part [ "?" sms-fields ]
      scheme         = "sms"
      sms-hier-part  = sms-recipient *( "," sms-recipient )
      sms-recipient  = telephone-subscriber ; defined in RFC 3966
      sms-fields     = sms-field *( "&" sms-field )
      sms-field      = sms-field-name "=" escaped-value
      sms-field-name = "body" / sms-field-ext ; "body" MUST only appear once
      sms-field-ext  = 1*( unreserved )
      escaped-value  = *( unreserved / pct-encoded ) ; defined in RFC 3986


The definition also provides three examples,

     sms:+15105550101
    
       This indicates an SMS-message-capable recipient at the given
       telephone number.  The message is sent using the user agent's default
       SMS delivery method.
    
     sms:+15105550101,+15105550102
    
       This indicates SMS-message-capable recipients at the given telephone
       numbers.  The identical message should be sent to both recipients
       using the user agent's default SMS delivery method.
    
     sms:+15105550101?body=hello%20there
    
       In this case, a message (initially being set to "hello there", which
       may be modified by the user before sending) will be sent via SMS
       using the user agent's default SMS delivery method.  

---

**Working solution**

I've created the following regex that seems to loosely validate the formal definition:

`/^sms:([\+\-\(\)\d]*\d[\+\-\(\)\d]*,?)+([?&]body=.+)?$/`


**Test Cases**

This regex has produced correct validation against the following test cases:


```| Test case                   | Result  | Expected Value |
|-----------------------------|---------|----------------|
| sms:1234567890              | Valid   | Valid          |
| sms:+1234567890             | Valid   | Valid          |
|  sms:+1234567890,0987654321 | Valid   | Valid          |
| sms:+1-234-567-8901         | Valid   | Valid          |
| sms:+1234@#567890           | Invalid | Invalid        |
| sms:+1234a567890            | Invalid | Invalid        |
```

  [1]: https://tools.ietf.org/html/rfc5724