This last recipe is more of a tip than a recipe; if you've got some JSON you developed using another programming language or by hand, you can easily create a TypeScript interface for objects to contain the JSON by using Timmy Kokke's json2ts website.
Simply go to http://json2ts.com and paste your JSON in the box that appears, and click on the generate TypeScript button. You'll be rewarded with a second text-box that appears and shows you the definition of the TypeScript interface, which you can save as its own file and include in your TypeScript applications.