TypeScript regression

[whaatt]

#55 added auto-generated TypeScript types, but it seems like some of the functions (e.g. h3ToGeoBoundary) that return an array of arrays (i.e. Array[]) don't type-check properly in TypeScript, since the compiler expects the outer Array to have a type parameter:

h3-js/lib/h3core.js

Line 566 in c5f653f

* @return {Array[]} Array of [lat, lng] pairs

The fix is likely to specify the inner-most type explicitly (e.g. Number[][]) in the JSDoc.

[nrabinowitz]

Thanks for the bug report. We probably need to add a check in Travis CI to catch this kind of issue.

[whaatt]

Will this be addressed in any upcoming releases? Would love to have type enforcement when using this library in TypeScript (I'm stuck on 3.4.0 at the moment).

Thanks!

[nrabinowitz]

Yes, I'd like to fix it in the next release. I'm not as familiar with TS as I ought to be - is there a standard type-checking step we could do in CI that would catch this?

[whaatt]

Nothing off-the-shelf AFAIK, but it's simple enough to add a script in package.json, e.g.:

"scripts": {
  // ...
  "type-check": "tsc dist/types.d.ts"
  // ...
}

I'm guessing you do an npm install already in your CI, so you could add typescript as a dev dependency to get tsc in your local environment. If I run this command now, I get the following error output:

WorkMac:h3-js sanj$ tsc dist/types.d.ts
dist/types.d.ts:80:75 - error TS2314: Generic type 'Array<T>' requires 1 type argument(s).

80     function h3ToGeoBoundary(h3Index: H3Index, formatAsGeoJson: boolean): Array[];
                                                                             ~~~~~

dist/types.d.ts:137:36 - error TS2314: Generic type 'Array<T>' requires 1 type argument(s).

137     function polyfill(coordinates: Array[], res: number, isGeoJson: boolean): H3Index[];
                                       ~~~~~

dist/types.d.ts:149:83 - error TS2314: Generic type 'Array<T>' requires 1 type argument(s).

149     function h3SetToMultiPolygon(h3Indexes: H3Index[], formatAsGeoJson: boolean): Array[];
                                                                                      ~~~~~

dist/types.d.ts:228:93 - error TS2314: Generic type 'Array<T>' requires 1 type argument(s).

228     function getH3UnidirectionalEdgeBoundary(edgeIndex: H3Index, formatAsGeoJson: boolean): Array[];
                                                                                                ~~~~~


Found 4 errors.

[nrabinowitz]

Thanks, this is perfect.