export class EnvError extends TypeError { constructor ( message ? ) { super ( message ) ; Object . setPrototypeOf ( this , new . target . prototype ) ; Error . captureStackTrace ( this , EnvError ) ; this . name = this . constructor . name ; } } export class EnvMissingError extends ReferenceError { constructor ( message ? ) { super ( message ) ; Object . setPrototypeOf ( this , new . target . prototype ) ; Error . captureStackTrace ( this , EnvMissingError ) ; this . name = this . constructor . name ; } }