Office Web Add-in Debugging in VS Code

Another recent announcement that has me excited is the ability to debug Office Web Add-ins directly from VS Code. Before this recent announcement, it was a hit or miss proposition. There was Visual Studio 2019, that did a pretty good job. But I liked the lightweight simplicity of VS Code. Visual Studio 2019 seemed too too heavy-weight. It’s hard to put my finger on how or why, but I really enjoy VS Code for Web Add-in development so much better. Except for debugging…

So, to debug, I actually did most of my dev/test in the web versions of Office (Excel online, Outlook online, etc.). Then came the Edge Developer Tools Preview which helped debug task pane add-ins in the full clients. But that did not help with things like the On Send event in Outlook or other UI-less functions. So, it was a struggle at times.

Now that has all changed!!!

The process is a tad more complicated than I like, but it does work. Essentially, you need to:

  1. Run VS Code as administrator
  2. Install the extension in VS Code by pressing CTRL + SHIFT + X and searching for the “Microsoft Office Add-in Debugger”
  3. Add the following code to the .vscode\launch.json file to enable Office Debugging in your project. You will need to update line #7, and replace the uppercase HOST text with the host application for your Office add-in.
{ 
   "type": "office-addin", 
   "request": "attach", 
   "name": "Attach to Office Add-ins", 
   "port": 9222, 
   "trace": "verbose", 
   "url": "https://localhost:3000/taskpane.html?_host_Info=HOST$Win32$16.01$en-US$$$$0", "webRoot": "${workspaceFolder}", 
   "timeout": 45000 
}

NOTE: If you create a new Office project with Yeoman, you will not need to add this line, it will be part of the default template going forward.

  1. Press CTRL+SHIFT+D to then open the Debug pane, select Attach to Office Add-in option from the drop down list at the top of the pane, and press F5 to start debugging.
  2. You can now set breakpoints, see variable values, etc.
Attach to Office Add-ins menu option