Compilation / type checking depends on a lot of trees of typed data, and operating on those tree nodes. That's something where a statically typed language with

Compilation / type checking depends on a lot of trees of typed data, and operating on those tree nodes. That's something where a statically typed language with custom data structures that allows for optimised representations makes a big difference, and where a lot of the fancy optimisations in v8 don't work so well. There is a reason Typescript moved to a typed language.