[agentultra]

Definitely painful. After trying to get a team to adopt and gradually type a large codebase for the last 2.5 years I can say that gradual typing is a dream. In practice you write more code than you end up typing as you go and the project is never 100% complete.

If something gets typed as `any` all bets are off and there are no benefits. So people don't end up running the type checker during development anyway. Which defeats the purpose.

There are small places where it is useful -- some developers on the team had never used a type system before and found that it helped them eliminate errors from their code before they even ran the program.

But overall... agree, Typescript/Flow -- they were great experiments and useful -- but I'd rather see ways for us to adopt better languages. Elm, Purescript, Haskell, F# -- Javascript is great for projects of a certain size... but once you get to a large team and many tens-of-thousands of lines of it... discipline will only get you so far.

[spraak]

> If something gets typed as `any` all bets are off and there are no benefits.

Then why allow `any`? Using TS without the compiler and linter configs tuned to your benefit is like trying to use a plane only as a car. No discipline required if you let yourself fly with settings that set you up for long term success later.

Also, Flow is not on the same level as TS. It's a dead project and was never fully baked.

[agentultra]

Because sitting around and typing tens of thousands, maybe hundreds of thousands of lines of code is not super productive?

That was the whole sell of "gradual typing," was it not? That you could turn it on, type everything as `any` then add better types as you go with the goal of eventually having a fully typed code base.

Except in our experience you'll always be playing catch up and never get to the promised land.

[spraak]

Don't do gradual typing, is what I'm saying. Start a project with the compiler and linter tuned strict and you'll do well. But if you have to go gradually and you have a goal of typing an untyped codebase, then just introduce a rule at a time from a list of rules you'd like in the end. Each rule should be a single commit or single PR (or Epic, or whatever granularity required)

> Because sitting around and typing tens of thousands, maybe hundreds of thousands of lines of code is not super productive?

Your project either doesn't benefit from static types or you're not seeing the benefits. I agree it's annoying to convert a JS project to TS, but TS in the end has been a huge boon to our overall velocity (long term) considering bugs, refactoring, and service to service edges.

[agentultra]

> But if you have to go gradually and you have a goal of typing an untyped codebase, then just introduce a rule at a time from a list of rules you'd like in the end.

This was the plan. In a similar fashion to bringing a legacy code base under test we would commit to bringing this code base under type coverage. We started by adding explicit type signatures at the start and refining the types as we worked on the modules. What we ended up with is an archipelago of typed modules.

This has the consequence of forcing the developer to be aware of the coverage of the module they're working with. On our team I don't think there were enough people who had experience with strongly typed languages on board -- we're a JS shop. This meant we had to teach our teams how to think and design with types as we went along... and as deadlines approach and teams work towards their goals sometimes... that escape hatch is too tempting.

So your archipelago spends most of its time shifting. Some old, crufty modules never end up getting typed. New modules are well typed. And there are too many of the former to enable strict checking without overloading the developers.

It's not simply a technical problem but a social one too.

> Your project either doesn't benefit from static types or you're not seeing the benefits.

I believe types benefit the programmer and help us reason about programs. We've been seeing benefits there. It has helped some of the more junior developers learn how to write better code.

One boost has been that I started teaching a weekly class in Haskell that some of our developers opt into and that has had a positive effect. A more strict language has helped demonstrate how to structure programs and think in types. Which has helped them, they say, write better Javascript (even though I'd never recommend learning Haskell to "become a better programmer," you'll walk away frustrated).