I'm confused; how is jsdoc an alternative to typescript? They serve totally different functions.
Personally I don't think there's any good argument not to use typescript over javascript
Personally I don't think there's any good argument not to use typescript over javascript
This is how type checking works in python and ruby, rather than there being a compilation step like typescript.
The difference between this approach and the typescript approach is that typescript isn’t valid JavaScript, you need a build step that converts it. JavaScript with JSDoc type annotations is valid JavaScript, just with special comments in it, so it doesn’t need to be converted before it is run.
Next time you try to use that function the tooling (VS Code) will highlight the Type required by it as both documentation and a dynamic check - this fn input is missing X property.
Imagine it as a TS light version, where tooling and docs helps you write well-documented typed code that isn't checked for validity at compilation.
All the logic that is important is typed: all inputs, outputs. Each function is documented in terms of the program IO and what it should do and why (description).
There's no typed guard rails in place. You could pass an object that doesnt follow a type, but with team agreements, reviews, testing, and diligence you wouldn't. In TS you bypass process because the compiler does those checks for you.
To actually force runtime compliance to types and further get to a statically typed vision I used object validation schema. Each complex fn input would have a schema and we would validate against that.
In such a way you have some typing, documentation, and some static typing.
Since JS was never build with types or static typing as a first class citizen (like other languages are) there's less friction in scenarios where JS is too multifaceted or loose. This is the "have your cake and ear it" reply: you have types, documentation, runtime type checks for what matters, but you stay native to JS and avoid full static typing, remove the need for TS compiler.
Before type annotations were officially added in python 3.5, you could still use mypy for type checking. The only difference being that the type hint format wasn’t standardized across tools.