Promise.irregardless
Based on a reddit discussion, this adds the following functions to the Promise prototype:
Promise.prototype.irregardlessPromise.prototype.regardlessPromise.prototype.always
All of these are just aliases for Promise.prototype.finally, and thus you may need a shim to provide that.
ES3 is not supported.
Preserving any remaining sanity of any potential users is outside of the scope of this project. You have been warned.