The TypeScript Tax - JavaScript Scene - Medium →
Eric Elliott with a nuanced, data-driven analysis of the pros and cons of TypeScript:
That said, TypeScript hit an inflection point in 2018, and in 2019, a large number of production projects will use it. As a JavaScript developer, you may not have a choice. The TypeScript decision will be made for you, and you shouldn't be afraid of learning and using it.
But if you're in the position of deciding whether or not to use it, you should have a realistic understanding of both the benefits and the costs. Will it have a positive or negative impact?
In my experience, it has both, but falls short of positive ROI. Many developers love using it, and there are many aspects of the TypeScript developer experience I genuinely love. But all of this comes with a cost.