TypeScript is building in popularity and JQuery is remains one of the most popular JavaScript frameworks. Consequently you will typically want to use them together in the same project at one stage or another.
If you do want to use JQuery within your TypeScript files in Visual Studio 2017, you need a "DefinitelyTyped" definition specifically for jQuery. This will allow Visual Studio to correctly recognise jQuery objects when validating and compiling (or transpiling based on your preferred terminology).
If you do want to use JQuery within your TypeScript files in Visual Studio 2017, you need a "DefinitelyTyped" definition specifically for jQuery. This will allow Visual Studio to correctly recognise jQuery objects when validating and compiling (or transpiling based on your preferred terminology).
DDK