In this chapter, we went through some of the most important projects that Microsoft promotes as part of its Open Source ecosystem.

First, we reviewed the evolution of "open source" projects since the initial movements and revised some of the new tools and technologies under the open source initiatives, including how to program with Node.js from Visual Studio.

Then, we moved on to the Roslyn set of tools and services and explored how to install the tools, identify the Syntax Object Model, and program a basic analyzer with code refactoring capabilities and understand how to debug it.

Finally, we took a tour of the main language features of TypeScript, studying some of the most meaningful and proper definitions of the language and checking the excellent support we get in the code editor thanks to its static type system.

In the next chapter, we'll cover the concept of Software Architecture, from high-level abstract concepts to low-level implementation. I will outline a step-by-step guide on designing a .NET application from the ground up.