Discriminated unions, conditional types, mapped types, template literal types, recursive type aliases, higher-kinded type patterns, generic constraints with conditional inference, the infer keyword, never type exhaustiveness checking, const assertions, readonly tuple and array inference, exact object types, key remapping in mapped types, indexed access types, variance annotations, assertion signatures, strict null checking with flow-sensitive narrowing, definite assignment assertions, the satisfies operator, declaration merging, module augmentation, symbol-typed properties, type-safe enums

…and not written via comments

I’ve found that the system works pretty well. It’s not perfect, but I can’t think of a better solution.

Not sure this will save you time and money, but it is very comprehensive.