ES-Class Utility

es-class is a JavaScript utility designed to provide a class-like structure with features reminiscent of ES6/ES7, such as `extends`, `constructor`, `super`, `with` for mixins, `static` properties, and `implements` for light interface checking. Its primary differentiator was its robust backward compatibility, targeting environments as old as ES3 (Internet Explorer 6, Android 2) while offering a forward-looking syntax during the transition to native ES6 classes. The package's current stable version is 2.1.1. However, development appears to be abandoned, with no new releases or maintenance activities for several years, making it a legacy solution for modern JavaScript development. It aimed to bridge the gap between pre-ES6 JavaScript and the then-upcoming native `class` syntax.