Leaflet.js total refactor!

[GoToLoop]

After taking a hard look at Leaflet.js (also TileMap.js) in order to find a more proper solution for some1 from the Processing's forum: https://Forum.Processing.org/two/discussion/26239/p5-js-mappa-js-unable-to-place-map-in-parent-div#Item_4

I've found out this class Leaflet got some tiny minor cosmetic issues. And that I could refactor it. :P

1. Current latest Leaflet.JS' version is now 1.3.1. But this class is loading 1.3.0 instead. So I've changed 'https://unpkg.com/[email protected]/dist/leaflet.js' to 'https://unpkg.com/[email protected]/dist/leaflet.js'. @1.3, rather than @1.3.0, will automatically pick latest version from range v1.3.0 to v1.3.9. I don't think patch updates are that dangerous, are they?

2. In canvasOverlay(), you've got an custom subclass from L.Layer named as L.overlay. However, according to JS/Java's conventions, class names should be capitalized. Therefore I've renamed L.overlay to L.Layer.Overlay. Then made a custom L.overlay() function which instantiates that just renamed subclass. ^_^ Given the now wrapper function got the same name as the previous subclass' name, no API call had been changed!

3. Besides that renaming and a new wrapper function in its place, I've found some instructions about extending class L.Layer below: http://LeafletJS.com/examples/extending/extending-2-layers.html However, your approach differs greatly from the article above. You use an arrow function for L.Layer::onAdd() method, permanently sealing its this to that of subclass Leaflet's. You do that in order to access this.canvas inside L.Layer::onAdd(), I know. Well, I've refactored it to access this.canvas as a closure variable simply called canvas there.

Well, those are my main changes. There are many more tiny 1s throughout the file though. :D
Got no idea how much you're gonna like them. Just tell me which 1s to revert back then.

P.S.: Not tested at all!!!

[codecov-io]

Codecov Report

Merging #10 into master will decrease coverage by 0.22%. The diff coverage is 0%.

@@            Coverage Diff            @@
##           master     #10      +/-   ##
=========================================
- Coverage   44.52%   44.3%   -0.23%     
=========================================
  Files          14      14              
  Lines         393     395       +2     
=========================================
  Hits          175     175              
- Misses        218     220       +2

Impacted Files	Coverage Δ
src/providers/tile/Leaflet.js	1.88% <0%> (-0.08%)	:arrow_down:

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[cvalenzuela]

wow, this is amazing! thanks for the PR!

I left some comments, but regarding your points:

1. Perfect. Makes total sense.

2. Seems good to me, I just left some questions on the review.

3. I didn't know that! leaflet had a major released not so long ago and I haven't updated this repo to reflect that.

I will test it and let you know how it goes. I still haven't implemented all automatic tests so part of it will go manually.

Let me know your comments so we can move forward and merge

[ChaimStanton]

I think this commit may change the id attribute of the layer from what it was previously as #mappa to #leaflet. See my issue #47 for more info.