Visual Studio 2017 not compiling typescript

Check ts file properties in Solution explorer. If Build action = Content, change it to TypeScript file

in a .NET Core 2.1 project in which I has used VS's New Project template for React, I had to edit the .csproj and change <TypeScriptCompileBlocked>true</TypeScriptCompileBlocked> to false.

Why does this option even exist!?!?!