Babylon.js is a big project with increasing contributions since its creation on GitHub. It provides you with a lot of functions and, sometimes, with a lot of parameters for more flexibility. The TypeScript language is useful for robust code as its goal is to improve and secure the production of JavaScript code.
TypeScript (TS) is a free and open source language developed by Microsoft. It is a compiled language to produce JavaScript (the TS code is, in fact, transcompiled) and provides a static typing system, which is optional. The typing system is used in Babylon.js in order to get a cleaner and more descriptive code. It means that if a function has a lot of parameters, it's easier to fill and understand them instead of always using the documentation as a reference. Moreover, it allows developers to declare classes (as the ECMAScript 6 specifications do) and interfaces for a better understandable architecture and structure of code.
The typing system is powerful as it allows developers to create interfaces, enumerated types, and classes and handle generics and union typing. Overall, developers use the typing system for a better understanding and security of the libraries that they are building and using.
The TS language supports inheritance (classes) and also provides access specifiers (private / public / protected) to modify the access rights for the classes' members. Then, developers can see at a glance the members that they can use and modify.