Fix issue that broke themes #142

[nlfurniss]

Issue

This commit fixes an issue that arose after I removed jQuery from the addon. It also adds a test to prevent regressions.

To ensure everything works as it used to, I also ran the new test against v0.6.0 (pre jQuery removal) and it passes.

Current solution

This PR adds deepmerge as a dependency to take the place of jQuery.extend(true, ...);. As it is released as an ES6 module, it was necessary to use a transform to import it into ember-highcharts.

Downside to my approach

Using the es6 transform requires ember-cli >= 2.16. Ember-cli 2.16 was introduced 10 months ago, so while there might be some users who cannot take advantage of this change, presumably the gross majority won't find this a problem.

Other possible solutions

• Use ember-auto-import
  This is a great addon, but if the consuming app has a CSP that disallows eval, it won't work.

• Inline deepmerge
  Seemed hacky, but has no ember-cli support issues.

[RobbieTheWagner]

@nlfurniss can we use ember-copy to make a deep copy? That is what you are looking for right, to deep copy something?

[nlfurniss]

No, because we're not trying to copy options, but trying to merge the theme and chartOptions

[RobbieTheWagner]

@nlfurniss how about Object.assign? There has to be something we can use that doesn't require another package.

[nlfurniss]

assign doesn't do deep merging. It's fine for simple and flat objects, but chart themes and options are complex and deep.

[RobbieTheWagner]

@nlfurniss can we use ember-cli-node-assets to import deepmerge then? It would be good to not require ES6 transforms. if we can, although it's not necessarily a deal breaker. I've done shims for things with it before, for example https://github.com/shipshapecode/ember-vivus/blob/master/index.js

[nlfurniss]

@rwwagner90 good call with node-assets, didn't know about it.

Updated the implementation, should be good to go with no change to supported versions of ember-cli. The umd package is 567B when minified and gzipped, so not a large price to pay to restore this critical functionality.