I think the bigger leap is between having a transpiler and not having one. If you are already using babel for example, you can have it compile Typescript (basi

I think the bigger leap is between having a transpiler and not having one. If you are already using babel for example, you can have it compile Typescript (basically strip away all the type annotations). At that point typescript is like an optional set of javascript features. Also the typescript compiler is very flexible, in terms of what it enforces. You can vary it from being really lax to pretty strict. You can use babel to do the transpilation, then have the typescript compiler run off to the side doing typechecks / providing your editor with code completion.