InvalidCharacterError: "fred"

Question

I am sure his must be a newbie question. In simple terms I wanted to define my first Polymer-dart component. Only I keep kicking my toe on the same speed-hump. To keep things very simple, I've stripped it back to a very simple example.

I did a simple rename of the example: 'stopwatch'component from the Dart component Polymer-dart tutorial:

• Define a Custom Element

I had errors similar to the one in the question title, so the renamed component is:

• 'fred' ... from: 'tute-stopwatch'

When this is done, I get the error trace below. It looks to me that the name is my problem. I confirmed this by running the example after each incremental change (what else can you do?). I retained the file names:

• tute_stopwatch.html
• tute_stopwatch.dart

From the example, and only changed the component label name. That means a change in 3 x files.

1. index.html
   
   • <fred></fred>
     
     • from: <tute-stopwatch></tute-stopwatch>
2. tute_stopwatch.html
   • <polymer-element name="fred">
     
     • from: <polymer-element name="tute-stopwatch">
3. tute_stopwatch.dart
   • @CustomTag('fred')
     • from: @CustomTag('tute-stopwatch')

Although, I can't say having to update three(3) things for one simple change is ideal, it is still very basic and very simple to 'make' a new element with Polymer-dart once you have a model definition.

Apart from, what went wrong? I guess a second question I can ask is, what does the:

• 'The type name is invalid.' ... Mean?

The question is decidedly a newbie question. However because the 'solution' is not obvious or intuitive, I've missed something. Oh and the error makes No Sense (to mere mortals). Muy gracias ...

---

Exception:

Uncaught Error: InvalidCharacterError: Registration failed for type 'fred'. The type name is invalid.
Stack Trace: 
#0      _Utils._register (file:///E:/b/build/slave/dartium-win-full-stable/build/src/dart/tools/dom/src/native_DOMImplementation.dart:450)
#1      _Utils.register (file:///E:/b/build/slave/dartium-win-full-stable/build/src/dart/tools/dom/src/native_DOMImplementation.dart:446)
#2      HtmlDocument.register (file:///E:/b/build/slave/dartium-win-full-stable/build/src/build/Release/obj/global_intermediate/blink/bindings/dart/dart/html/HtmlDocument.dart:266)
#3      PolymerDeclaration.registerType (package:polymer/src/declaration.dart:241:22)
#4      PolymerDeclaration.register (package:polymer/src/declaration.dart:164:17)
#5      PolymerDeclaration._register (package:polymer/src/declaration.dart:114:13)
#6      PolymerDeclaration.registerWhenReady (package:polymer/src/declaration.dart:109:14)
#7      _notifyType (package:polymer/src/declaration.dart:476:49)
#8      Polymer.register (package:polymer/src/instance.dart:65:16)
#9      _loadLibrary (package:polymer/src/loader.dart:196:25)
#10     _loadLibraries (package:polymer/src/loader.dart:89:19)
#11     _initPolymerOptimized (package:polymer/src/loader.dart:54:17)
#12     _rootRun (dart:async/zone.dart:710)
#13     _ZoneDelegate.run (dart:async/zone.dart:440)
#14     _CustomizedZone.run (dart:async/zone.dart:650)
#15     initPolymer (package:polymer/src/loader.dart:37:33)
#16     main (package:polymer/init.dart:23:22)

Exception: InvalidCharacterError: Registration failed for type 'fred'. The type name is invalid.  undefined (undefined:0:0)

Answer 1

The tag name of polymer elements must contain a dash to differentiate them from standard DOM elements.