I'm happy that the static type guard rails exist. I mainly work on e-commerce codebases that have been operating for on average more than 5 years, have had a l

I'm happy that the static type guard rails exist. I mainly work on e-commerce codebases that have been operating for on average more than 5 years, have had a lot of different developers work on them, and are typically large enough (1 million lines of code or more), that I can't keep it all in my head. For this type of work, it's very nice to have static types, as some of the code has tests, some don't, and at least the static type is a sort of enforced guard rail. Ideally, everything would have tests, and most projects I work on we try to move in that direction with various amounts of success. For me, the most challenging changes can be Javascript changes where there are no tests and no types.