TypeScript is great for adding some type-safety to JavaScript apps. I don't think it can/will ever replace JavaScript, there are some things you can do in JavaScript you just can't do in TypeScript. For example higher-kinded types aren't a thing in TypeScript, so you can't have "generic generics" that can support some of the interesting things you can do with a dynamic language like JavaScript.
TypeScript shines more in providing safety and refactorability for large apps and teams.