Data classes, co-routines and flows, internal dsl support, null checks, smart casts, type inference, an IDE that is actually smart, a standard library that is a

Data classes, co-routines and flows, internal dsl support, null checks, smart casts, type inference, an IDE that is actually smart, a standard library that is a bit more comprehensive than what a browser has, a lot of kotlin and kotlin multiplatform libraries, and more. The general feel of the language is that of one developed by people who deeply understand what a nice language should feel like. It has a lot of features and syntactic sugar that eliminate verbosity, make things more straight forward to use and so on. It really shows that this is a language designed from the ground up to be genuinely nice to use by people who really know what they are doing because their core business is selling developer tools to developers. I like typescript. It is a big upgrade from Javascript and MS has a lot of the same mindset that Jetbrains brings to the table in terms of developer friendly-ness and language ergonomics. Kotlin has most of the features that make typescript nice but without the whole business of trying to keep it compatible with javascript. That adds a lot of complexity, ambiguity, and weirdness to typescript that Kotlin simply does not have or need.