Install npm and the VS Code extension development tools:
brew install npm
npm install -g yo generator-code
npm install -g @vscode/vsce
Then to create a .vsix package for installing, cd to the root folder of the extension and enter
vsce package
This will create a .vsix file that can be installed with code. Note that if you get an error about changing README.md, you have to change the first few lines of the file. Apparently, vsce checks for this to encourage you to write some real documentation for the extension before publishing it.
You can install the extension with
code --install-extension todotxt-mode-0.0.1.vsix
I had to restart VS code to see the effect. You can uninstall it from the UI or using code --uninstall-extension.
You can publish new versions with vsce publish. I just manually change the version in package.json and then package it and publish it.
vsce publish
Make sure you udpate everything including CHANGELOG.md and check everything in and push first.
I've also started publishing to OVSX, described here: https://www.gitpod.io/blog/open-vsx/
npx ovsx publish -p <token>