I've worked with both. And I have to say: It depends. Mostly I feel like typescript slows me down A LOT. In my opinion, the better your code style, guidelines, linting, infrastructure, error reporting and tests - the less you need typescript. I worked in a team that had about 150 micro-apps and services, it was maintained by roughly 15 devs. Each microservice had it's very small scope and it was very very easy to work with it. Everything was very predictable, which made it easy to work without having types.