Sharp and webpack 2 support (aka v1 🌟)

[jstcki]

Adds support for processing images using sharp which is much faster than Jimp or even ImageMagick.

I built on top of @langri-sha's work mentioned in #2, but instead of replacing Jimp, I added sharp as an option. Currently, you can enable it by specifying it as an adapter in the webpack config (default is still Jimp):

{
  responsiveLoader: {
    adapter: require('responsive-loader/lib/adapters/sharp')
  }
}

Auto-detection of sharp could still be added. This approach has the nice benefit that anyone can supply their own adapters once the API is stable.

I also reorganized and changed a few things, most notably:

• added a Babel build step to ensure Node 4 compatibility (I also want to add Flow types at some point, this prepares for that)
• replaced tape with Jest because snapshots are super-nice to test a loader's output
• added a few more tests to make sure the adapters work in the same way

After some fiddling I got the tests to pass on Travis. sharp builds fine on the trusty environment but oddly the output of sharp seems to differ on Linux and macOS, so I had to switch to the osx environment in order to make the tests pass. I wonder if there's a better solution to this …

[novascreen]

Any chance you'll merge this soon? Anything I can do to help getting this done?
Otherwise I'll have to find a different solution. Jimp is just too slow especially with a build for server, client and storybook. Takes 1-2 minutes for every start.

[RichAyotte]

The performance improvement is dramatic with this patch. I hope you can merge it soon.

[wereHamster]

Somebody published this branch as a separate package to NPM: https://www.npmjs.com/package/responsive-loader-sharp, feel free to use that in the meantime.

[jstcki]

That package's README is wrong. I will try to finish the remaining work in the next few days and release an "official" version.

[jstcki]

Alright, I've just published v1.0.0-rc.1 including sharp and webpack >= 2 support.

Along the way, I dropped support for webpack 1 and had to change the import syntax a bit. Make sure to read the change log and the new README.

Please test this release and then we'll finally get it out the door 😄 . Thanks for the patience!

PS: I'll be adding the pending new features once this is done.

[wereHamster]

I won't be able to test this because my current project still uses webpack 1, and I don't plan to upgrade to webpack 2 in this iteration.

[RichAyotte]

Works great. Thanks.

[jstcki]

Merged and released as v1.0.0 🎉