How do I run a typescript vscode extension from a local clone of the git repository?

Question

I edited the javascript of a vscode extension installed in .vscode/extensions and made a useful change.

So, I forked and checked out the git repo hoping to make a pull request. I found that the javascript I had edited was generated from typescript. The code was similar enough, so I made the same edits. Now I want to load this extension to test it before making a pull request.

I tried copying the modified repo contents to .vscode/extensions, and it shows up in the list of installed extensions. No matter how much I reload, disable, and re-enable the extension from inside of vscode, though, no javascript is generated.

I've made sure tsc is installed and on my PATH, but this doesn't seem to make a difference. No out directory is created, no messages appear in the debug console -- in short, it doesn't appear that anything is kicked off to compile the typescript at all.

The documentation I've found only talks about creating a new extension, not getting a modified existing extension to work. Any pointers would be greatly appreciated.

(This is on a Debian Linux system.)

Answer 1

Open your repo folder in vscode as usual. Then create a launch config for extension development ("Add Configuration" in the Debug section, launch.json editor):

This should add a new launch config as extension host, with a prelaunch task of "tsc". You can then use this to launch a second vscode instance in debug mode where you see your changed extension, by starting a debug session.