TypeScript: Documentation - TypeScript 3.9

Writing a Recursive Utility Type in TypeScript :: Building Better

how to extends a module in typescript - Stack Overflow

Classes in TypeScript

Type System Features - CodeProject

How to extend a Type in TypeScript

Typescript Tutorial #34 Extending interfaces in TypeScript

Empty interface extending type can give incorrect field type · Issue #32790 · microsoft/TypeScript · GitHub

extension methods - Typescript - How to extend a class in a namespace? - Stack Overflow

Diagram of every possible TypeScript type · GitHub

Unable to specify return type of class extends T implements IFooable · Issue #15001 · microsoft/TypeScript · GitHub