HapticKey
HapticKey is a simple utility application for MacBook with Touch Bar that triggers a haptic feedback when tapping keys on Touch Bar.
Since Touch Bar is just a flat panel, there are no feedback other than visual change of the key displayed, it is terribly uncomfortable especially when tapping ESC key, like while using vim. By adding a haptic feedback, which is vibrating track pad not Touch Bar itself, it helps to improve the usage of Touch Bar keys.
Usage
Download a prebuild application binary from Releases page.
The application requires a permission to use Accessibility, as like the other applications that are listening system events.
To run application as a standalone, allow HapticKey.app in the Privacy panel of System Preferences.app under the Security & Privacy section.
To run application in Xcode, allow Xcode.app instead.
Overview
To build the application, you need to use Xcode 9.
This application is using CGEventTap to listen key down and up events.
Then, it triggers haptic feedbacks by using private APIs in MultitouchSupport.framework when the event meets the conditions.
Currently, the application is listening either ESC and F1, F2, etc. keys or tap gestures on Touch Bar.
You can implement your own HTKEventListener to extend the application to trigger haptic feedbacks on arbitrary events.