Above and beyond the concepts of classes, interfaces, and inheritance, the TypeScript language introduces a number of advanced language features in order to aid the development of robust object-oriented code. These features include decorators, generics, promises, and the use of the async and await keywords when working with asynchronous functions. Decorators allow for the injection and querying of metadata when working with class definitions, as well as the ability to programmatically attach to the act of defining a class. Generics provide a technique for writing routines where the exact type of an object used is not known until runtime. Promises provide the ability to write asynchronous code in a fluent manner, and async await functions will pause execution until an asynchronous function has completed.

When writing large-scale JavaScript...