Hello, I have a client that wants a layer in a Developer Edition WAB application to 'flash' or 'blink'. I think I've found the references in the JS API docs that I will need, but I'm wondering if it would be better to modify the existing WAB code somewhere, or should I build a new widget to keep the code isolated? If I did modify existing code, where would be the best place to insert my method?
The code for applications such as Web Apps and Dashboards is stored in JSON format and can be accessed via the ArcGIS Online Assistant (https://ago-assistant.esri.com/, click the "I want to..." drop down and select "View an Item's JSON"). I recommend using NotePad++ for editing, then pasting the code back into the AGO Assistant. You'll receive a warning notification when you enable editing.
If you add an additional widget, it will just get added to the JSON anyway, so I recommend editing the existing widget in the JSON. Make sure to paste a copy of the existing JSON into a different NotePad++ tab in case you break it! 😉
Good luck! I've edited JSONs and REST definitions heavily, and found it to be a direct route to all sorts of solutions.