Tableau Extension debug

Posted on February 6, 2021 in
2 min read

I've started digging a bit into Tableau Extensions API lately.

I had some troubles into setting up the proper debugging environment.

The documentation says that you can debug a Tableau Extension by using a local socket communication between Tablueau and an instance of Chrome browser. They suggest to download Chromium but I wanted to try using my current Chrome installation.

How to debug

Briefly, launch Tableau with the command line with:

open /Applications/Tableau\ Desktop\ 2019.4.app --args --remote-debugging-port=8696

then point Chrome to:

http://localhost:8696/

Select the Extension name you're working on and you should be able to inspect the DOM and see the console for your debugging purposes.

registerElement is undefined

The problem is that the DevTool throws an error and the debugging session is therefore blocked:

Uncaught TypeError: document.registerElement is not a function
    at Object.UI.registerCustomElement (inspector.js:2964)
    at inspector.js:2976
    at inspector.js:2978

The browser throws an error because document.registerElement is missing.

Indeed, it's deprecated since a long time and possibly removed from recent version of Chrome.

Downgrade Chrome

I've realized that the only solution would be downgrading Chrome for that specific purpose.

There is a better way to do that, you can download the Chromium version they suggest in the documentation, such as this one.

Alternatively, you can use the Chrome Embedded Framework version. You can find binaries for Mac and Win here.

It's works fine. You can log in the console what's going on in javascript and you can inspecting the DOM with the Element panel.

The only downside is that everytime you reload an extension from within Tableau, the connection stops and you need to reload the browser as well.

Want to interact? Reach me out on Twitter
Spotted a typo? Send a patch