Add IIFE.

src/core/fluent-date.js

@@ -1,9 +1,11 @@
 /**
 The HackMyResume date representation.
-@license MIT. Copyright (c) 2015 James Devlin / FluentDesk.
-@module fluent-date.js
+@license MIT. See LICENSE.md for details.
+@module core/fluent-date
 */
 
+(function(){
+
   var moment = require('moment');
 
   /**
@@ -26,7 +28,10 @@ function FluentDate( dt ) {
     this.rep = this.fmt( dt );
   }
 
-FluentDate/*.prototype*/.fmt = function( dt ) {
+  FluentDate/*.prototype*/.fmt = function( dt, throws ) {
+
+    throws = (throws === undefined || throws === null) || throws;
+
     if( (typeof dt === 'string' || dt instanceof String) ) {
       dt = dt.toLowerCase().trim();
       if( /^(present|now|current)$/.test(dt) ) { // "Present", "Now"
@@ -63,7 +68,9 @@ FluentDate/*.prototype*/.fmt = function( dt ) {
         var mt = moment( dt );
         if(mt.isValid())
           return mt;
+        if( throws )
           throw 'Invalid date format encountered.';
+        return null;
       }
     }
     else {
@@ -72,7 +79,9 @@ FluentDate/*.prototype*/.fmt = function( dt ) {
       }
       else if( dt.isValid && dt.isValid() )
         return dt;
+      if( throws )
         throw 'Unknown date object encountered.';
+      return null;
     }
   };
 
@@ -82,3 +91,5 @@ moment.monthsShort().forEach(function(m,idx){abbr[m.toLowerCase()]=idx+1;});
   abbr.sept = 9;
 
   module.exports = FluentDate;
+
+}());