This widget is a sample of how to create a "headless" widget for the Wed AppBuilder (WAB). By "headless," I mean it is invisible and it is loaded at startup. It can add new functionality to the WAB such as map tips on feature layers, modify the appearance/behavior of other widgets using Dojo's Aspect Oriented Programming techniques (aspect.before, aspect.after, aspect.around). The only limit is your imagination.
There is no live sample for this widget, as it is invisible.
I called it Anvil because the original "headless" widget I wrote is called Acme, and I wanted to stay with the Roadrunner theme.
This widget does nothing except show a message when it loads, and also if you double-click the map while holding down the Control and Alt keys. (The double-click while holding down the Control and Alt keys feature obviously won't work on devices without Control and Alt keys.)
If you want to drop this widget into the WAB and configure it in an app, you will need to copy its folder into the client\stemapp\widgets folder and then add it to the client\stemapp\predefined-apps\default\config.json file.
If you want to add this widget to an app you have already built with the WAB, then add it to the main config.json file like this: