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Are you really trying to say people couldn't build complex apps before TypeScript? I know of hundreds of examples that were made before TS... Complex apps stil

Are you really trying to say people couldn't build complex apps before TypeScript? I know of hundreds of examples that were made before TS... Complex apps still had lots of tests, which basically solve the same problem as TS is trying to address, without having to write a different language than what gets run by the browsers.

sdeframond 3y ago
How would you compare the overhead of writing tests un JS to the overhead of doing proper TS? Obviously tests are still useful in TS, but not as many I think. Also, the feedback loop of a static type system is, IME, much faster than with tests only.
- jdlshore 3y ago
  Speaking as someone who’s done both, you write the same tests either way. The main benefit of the type system is for IDEs, which have better code completion and automated refactorings when they can statically analyze types. Types also make type-related errors easier to debug: your tests will probably trigger the bug, but you’ll have to do some digging to figure out why. On the flip side, the TS type checker is painfully slow, the code is noisy, and you’ll waste a lot of time satisfying the type checker. For me, the sweet spot has been dynamic (runtime) type assertions in JS. Fast feedback loop, no transpilation hassles, good error messages when type-related errors occur. Downside is that now the editor can’t statically analyze types. Lately, I’ve been experimenting with using swc to transpile TypeScript without typechecking it. Now there’s a fast feedback loop and I use the IDE to discover type errors. (And the integration build checks types too.) I’ve just recently started this experiment, so jury’s out on whether it’s better than runtime type checking.
- capableweb 3y ago
  I end up having the same amount of tests in JS as in TS. I'm not really testing that the types are correct, but that functions work correct. So just because you're writing JS, doesn't mean that everything you would assigned types to in TS, you now write a unit test for itself. And my editor does the autocomplete thing seemingly just as well as the autocomplete I get from TS, even when I just write JS code normally.
okeuro49 3y ago
> Are you really trying to say people couldn't build complex apps before TypeScript? I said easily. Types remove whole categories of errors. I think the industry has generally found dynamic typing to be a mistake. Most dynamic languages are now trying to retrofit types.

sdeframond 3y ago

How would you compare the overhead of writing tests un JS to the overhead of doing proper TS? Obviously tests are still useful in TS, but not as many I think. Also, the feedback loop of a static type system is, IME, much faster than with tests only.

jdlshore 3y ago
Speaking as someone who’s done both, you write the same tests either way. The main benefit of the type system is for IDEs, which have better code completion and automated refactorings when they can statically analyze types. Types also make type-related errors easier to debug: your tests will probably trigger the bug, but you’ll have to do some digging to figure out why. On the flip side, the TS type checker is painfully slow, the code is noisy, and you’ll waste a lot of time satisfying the type checker. For me, the sweet spot has been dynamic (runtime) type assertions in JS. Fast feedback loop, no transpilation hassles, good error messages when type-related errors occur. Downside is that now the editor can’t statically analyze types. Lately, I’ve been experimenting with using swc to transpile TypeScript without typechecking it. Now there’s a fast feedback loop and I use the IDE to discover type errors. (And the integration build checks types too.) I’ve just recently started this experiment, so jury’s out on whether it’s better than runtime type checking.
capableweb 3y ago
I end up having the same amount of tests in JS as in TS. I'm not really testing that the types are correct, but that functions work correct. So just because you're writing JS, doesn't mean that everything you would assigned types to in TS, you now write a unit test for itself. And my editor does the autocomplete thing seemingly just as well as the autocomplete I get from TS, even when I just write JS code normally.

okeuro49 3y ago

> Are you really trying to say people couldn't build complex apps before TypeScript? I said easily. Types remove whole categories of errors. I think the industry has generally found dynamic typing to be a mistake. Most dynamic languages are now trying to retrofit types.