A talk about modern JS: ECMAScript 5, 2015 and 2016.
View the slides in your browser.
The sample app in the app directory is meant to be upgraded from old JS to modern JS one feature at a time, in parallel with the slides. The initial code is es3-with-options.js and the final code is es2016-with-options.js.
Similarly, the TypeScript code can be upgraded from straight-from-js.ts, which relies on type inference and has a few blind spots, to with-types.ts, which has type declarations and compiles successfully even if noImplicitAny is set to true in tsconfig.json.
This blog post has some additional information.