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Comment by danmaz74 | Hacker News Reader

Talking about flow, I was wondering: couldn't something like that be implemented just with comments, leaving us with actually 100% valid javascript? Eg:

  // @param somestring [String] yadda yadda
  // @return [Boolean]
  function somefunction(somestring) {
    // @type [Boolean]
    var ret;

    ...

    return ret;
  }

This would remove any type of "lock in" if you want to use it...

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Flow actually explicitly allows this[1] by just /* */ commenting out the flow type signatures. We use this in Aphrodite's code base[2] and it works pretty well.

[1]: https://flowtype.org/blog/2015/02/20/Flow-Comments.html

[2]: https://github.com/Khan/aphrodite/blob/master/src/generate.j...

I'd prefer that approach too, as I can also document things at the same time as providing type annotations; flow-jsdoc looks interesting, but I don't know how easy it would be to plug into a Babel/Webpack+Babel workflow:

https://github.com/Kegsay/flow-jsdoc

There's also comments support in Flow directly, but it's sadly (but understandably) hideous:

  function somefunction(somestring/*: string*/)/*: boolean */ {
     var ret/*: boolean */;
     ...
     return ret;
  }

(See https://flowtype.org/blog/2015/02/20/Flow-Comments.html)

Might be worth pointing out, the "documentation" package[1] can be used to generate jsdoc annotations suitable for Google Closure compiler from Flow type annotations.

It can also build really nice HTML documentation to.

[1] https://www.npmjs.com/package/documentation

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