HapticKey is a simple utility application for MacBook with Touch Bar that triggers a haptic feedback when tapping 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 a track pad not Touch Bar itself, it helps to improve the usage of Touch Bar. It is also optionally playing a sound effect or flashing the screen like a visual bell on terminal.
Download the latest pre-build application binary from Releases page. Note that these pre-build application binaries are not signed so you need to allow to execute it on Security & Privacy settings pane in System Preferences.
Also, the application may ask a permission to use Accessibility, as like the other applications that are listening system events.
To build the application from the source code, you need to use the latest Xcode 9.
This application is using CGEventTap to listen key down and up or tap events on Touch Bar.
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 events on Touch Bar.
You can implement your own HTKEventListener to extend the application to trigger feedbacks on arbitrary events.