feat: make domain optional (#209)

* make domain optional

* adjust indentation

README.md

@@ -125,8 +125,8 @@ cal.domain('sebbo.net');
 
 #### domain([_String_ domain])
 
-Use this method to set your server's hostname. It will be used to generate the feed's UID. Default hostname is your
-server's one (`require('os').hostname()`).
+Use this method to set your server's hostname. If provided, it will be used to generate the feed's UID.
+`require('os').hostname()` can be used to get your server's hostname.
 
 
 #### prodId([_String_|_Object_ prodId])
@@ -289,7 +289,10 @@ Empty the Calender.
 
 #### uid([_String_|_Number_ uid]) or id([_String_|_Number_ id])
 
-Use this method to set the event's ID. If not set, an UID will be generated randomly.  When output, the ID will be suffixed with '@' + your calendar's domain.
+Use this method to set the event's ID. If not set, an UID will be generated randomly.
+If your calendar's domain is provided, the ID will be suffixed with '@' + your calendar's domain.
+If you do not provide a calendar domain, generating an ID using the
+[uuid](https://www.npmjs.com/package/uuid) module is recommended.
 
 
 #### sequence([_Number_ sequence])

src/event.js

@@ -1059,7 +1059,12 @@ class ICalEvent {
 
         // DATE & TIME
         g += 'BEGIN:VEVENT\r\n';
-        g += 'UID:' + this._data.id + '@' + this._calendar.domain() + '\r\n';
+        let domain = this._calendar.domain();
+        if (domain) {
+            g += 'UID:' + this._data.id + '@' + domain + '\r\n';
+        } else {
+            g += 'UID:' + this._data.id + '\r\n';
+        }
 
         // SEQUENCE
         g += 'SEQUENCE:' + this._data.sequence + '\r\n';

test/test_event.js

@@ -1731,7 +1731,7 @@ describe('ical-generator Event', function () {
                 summary: ':)'
             }, cal);
 
-            assert.ok(event._generate().indexOf('UID:42@') > -1, 'without domain');
+            assert.ok(event._generate().indexOf('UID:42\r') > -1, 'without domain');
 
             cal.domain('dojo-enterprises.wtf');
             assert.ok(event._generate().indexOf('UID:42@dojo-enterprises.wtf') > -1, 'with domain');