This post shows you how to solve the problem can't find typescript compiler in Visual Studio.
Severity Code Description Project File Line Suppression State
Warning Your project specifies TypeScriptToolsVersion 3.5, but a matching compiler was not found. The latest available TypeScript compiler will be used (3.6). To remove this warning, install the TypeScript 3.5 SDK or update the value of TypeScriptToolsVersion.
Updating TypeScript in Visual Studio
In Visual Studio 2017 version 15.3 and later, the TypeScript version used is bound to individual projects.
Right click on your project, then select Properties.
Click TypeScript Build tab, then change TypeScript version to "Use latest available"
Next, You need to rebuild your project.
Or you can install TypeScript SDK version, that you get message from your Visual Studio.
In this case, we will install TypeScript 3.5.1 for Visual Studio.
You can easily search it from https://marketplace.visualstudio.com
This is a standalone, power tool release of TypeScript 3.5.1 for Visual Studio. It includes both the TypeScript experience for Visual Studio and a standalone compiler that can be used from the command line.