The JavaScript gotchas will still getcha, such as variable hoisting. I tend to forget they are still there when working in TypeScript, but that's my fault.

When you comfortable with JavaScript, there is nothing can scare you in TypeScript.

The only thing is - to get a best you need to prepare. If you using some library, I should find (or write, or generate) proper definition file for this library (Interface). But when you get all together - you have a lot of happy hours of coding :)