WIP: use rollup

[themre]

I created a quick branch to use rollup. I added turf functions. it's still big because it's without uglify (have this problem Turfjs/turf#1086), but it's size went from 1.3 to 0.95MB. also CSS images I copied next to CSS and didn't bundled them into CSS, because I didn't have time for embeding them.

[themre]

well... @DenisCarriere did awesome job in converting turf modules to ES. I extracted some methods from jsts to separate utils file. final bundle is now almost 300kB smaller (final is 284 kB). webpack is not suitable for this, bundle is 634 kB big.

[DenisCarriere]

👍 Sweet! Glad to hear it worked out, ideally we can keep making it smaller and smaller since there's a lot of dead code laying around a few dependencies, but it's a step forward!

[codeofsumit]

@themre @DenisCarriere great to see progress in this but I still think these optimization should be upstream in the dependency tree. So either turf or jsts as I don't think leaflet.pm's build should optimize it's dependencies, but only it's own code.

@DenisCarriere is that something you will incorporate in the served turf bundle or would you suggest to put it into leaflet.pm (and essentially any other library that uses turf)?

[DenisCarriere]

@codeofsumit All of these optimizations will be available in the next TurfJS release as CommonJS/ES Modules & UMD bundles, right now there's still a bit of tweaking on refactoring turf-jsts (for internal TurfJS purposes) later on these changes would one day land in jsts.

I wouldn't recommend adding your own jsts code in leaflet.pm since you won't see any optimized gains compared to importing ES modules from TurfJS, it will be exactly the same bundle size.

Ideally we would love to drop jsts entirely, however it's been proven VERY difficult to do so.

These are the modules which directly & indirectly depend on JSTS:

// JSTS Modules
export {default as difference} from '@turf/difference';
export {default as buffer} from '@turf/buffer';
export {default as union} from '@turf/union';
export {default as intersect} from '@turf/intersect';

// JSTS Sub-Models
export {default as dissolve} from '@turf/dissolve';
export {default as hexGrid} from '@turf/hex-grid';
export {default as mask} from '@turf/mask';
export {default as squareGrid} from '@turf/square-grid';
export {default as triangleGrid} from '@turf/triangle-grid';
export {default as interpolate} from '@turf/interpolate';

If you import any of these modules, you're bundle will increase by ~500KB.

Once TurfJS v5.1 is published, you can have a look at any more optimization for bundle sizes, but JSTS would be at the "smallest" size possible at the moment.

[codeofsumit]

guys, thanks for your work on this but I will close this now as the size optimizations should happen upstream in the dependency tree and leaflet.pm will only optimize it's own code.