Property-pane-access-control NPM

spfx-property-control-template

A template for Sharepoint Framework custom Property controls

Clone this repository
cd to the root and run npm link
Then run npm run dev. Typescript compiler will start running in watch mode and will recompile every time a file changes
cd to your sharepoint solution root and run npm link property-pane-access-control (or the name of the package if you rename it)
Run gulp serve, at this point you will need to also trigger a recompile of the webpart after you make changes to your custom control. If you want to work around it see this link.