What tutorial are you following? I googled official documentation of extension development and noticed that they have this line that defines a variable that you're having problem with:
import * as vscode from 'vscode';
#broken webview sidebar thing
zealous pollen
orchid plover
i followed @ benawad tutorial on youtube and tried to get it work using an example on github
zealous pollen
It would be helpful if you posted links to youtube tutorial and to an example on github.
orchid plover
tutorial -> https://www.youtube.com/watch?v=a5DX5pQ9p5M&t=2381s
his github example -> https://github.com/benawad/vstodo/tree/master/extension
