Use the Preferences API to make your extension configurable. Preferences can be configured per command or shared in the context of an extension. Required preferences need to be set by the user before a command opens. They are great a way to make sure that the user of your extension has everything set up properly.
A convenience function for type-safe access to the values of the preferences object.
Each preference name is mapped to its value and the defined default values are used as fallback values.