How to extend page-object to include non-standard HTML Elements

I am looking for tutorials or help on how to extend the page-object gem (github.com/cheezy/page-object) to support elements like the Angular mat-chip. This element is very similar to a check box, but isn't recognized as such by page-object. The closest things Ive found are here.

https://williamjamespowell.com/2012/12/01/extending-pageobjects/

https://williamjamespowell.com/2012/12/27/gxt-pageobject-widget-example/

These examples are 8 years old and I don't know if they would still work. Unfortunately that is the extent of what Ive found on how to extend page-object functionality.

What I would like to do is create a mat-chip class and wire it up so that I could use that just like I would checkbox from page-object. I just can't quite figure out what all the pieces are that have to be wired up.

I'm not an Angular person, so I stole a clickable mat-chip example from https://stackoverflow.com/a/47962183/1200545. Depending on your implementation, you may need to tweak the code below.

First off, Page-Object has a limitation when defining widgets that use a custom tag name - ie "mat-chip". To get around this, we will define an associated method/locator in Watir:

module Watir
  module Container
    def mat_chip(*args)
      HTMLElement.new(self, extract_selector(args).merge(tag_name: "mat-chip"))
    end
    def mat_chips(*args)
      HTMLElementCollection.new(self, extract_selector(args).merge(tag_name: "mat-chip"))
    end
  end
end

We can then create a widget and accessors in Page-Object:

class MatChip < PageObject::Elements::Element
  def self.accessor_methods(widget, name)
    widget.send('define_method', "check_#{name}") do
      self.send("#{name}_element").check
    end

    widget.send('define_method', "uncheck_#{name}") do
      self.send("#{name}_element").uncheck
    end

    widget.send('define_method', "#{name}_checked?") do
      self.send("#{name}_element").checked?
    end
  end

  def set(bool = true)
    click unless set? == bool
  end
  alias check set

  def clear
    set(false)
  end
  alias uncheck clear

  def set?
    attribute_value('aria-selected') == 'true'
  end
  alias checked? set?

  PageObject.register_widget :mat_chip, self, :mat_chip
end

You can then use the accessor, named "mat_chip", the same was as a checkbox:

class MyPage
  include PageObject

  mat_chip('mychip', index: 1)
end

page = MyPage.new(browser)
page.check_mychip
p page.mychip_checked?
#=> true
page.uncheck_mychip
p page.mychip_checked?
#=> false

Alternatively, you can use the mat-chip directly as a nested element:

page.mat_chip_element.check
p page.mat_chip_element.checked?
#=> true
page.mat_chip_element.uncheck
p page.mat_chip_element.checked?
#=> false