How do I create a custom element in dart?

Question

I am trying to make a custom element in dart. It should simply contain 2 buttons. It never actually makes it through the construction process...what am I doing wrong?

Answer 1

There are a few issues in your code.

• Custom elements need to follow the naming rules that they need to have a - in their name
• The element needs to be registered in order for the browser to be able to instantiate them
• The setup(...) method you added wasn't called, therefore not caption was added to the button
• Custom elements need to extend HtmlElement

DartPad example

See also:

• Registering custom element in Dart lang
• extendTag in Dart custom element