Prototype: String.prototype.truncate now explicitly converts its return value into a string if no truncation takes place. This prevents possible issues with methods expecting input data that is typeof == string.

CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* String.prototype.truncate now explicitly converts its return value into a string if no truncation takes place. This prevents possible issues with methods expecting input data that is typeof == 'string'.  [Thomas Fuchs, Tobie Langel, Sam Stephenson]
+
 * Event.findElement behaves as expected when the element passed matches the given selector.  Closes #8395.  [Mislav Marohnić, Tobie Langel]
 
 * Element.setOpacity now calls removeAttribute on the filter style on IE if no more filters remain, which makes Cleartype work properly.  Closes #8376.  [alexdemi, Thomas Fuchs]

src/string.js

@@ -48,7 +48,7 @@ Object.extend(String.prototype, {
     length = length || 30;
     truncation = truncation === undefined ? '...' : truncation;
     return this.length > length ? 
-      this.slice(0, length - truncation.length) + truncation : this;
+      this.slice(0, length - truncation.length) + truncation : String(this);
   },
 
   strip: function() {

test/unit/string.html

@@ -208,6 +208,9 @@
       assertEqual('foo boo boz foo boo boz foo...', source.truncate(0));
       assertEqual('fo...', source.truncate(5));
       assertEqual('foo b', source.truncate(5, ''));
+      
+      assert(typeof 'foo'.truncate(5) == 'string');
+      assert(typeof'foo bar baz'.truncate(5) == 'string');
     }},
     
     testStrip: function() {with(this) {