Builds with rollup "don't crawl"

[devleaks]

Type:

• [ x] bug ?
• [ ] feature
• [ ] enhancement
• [x ] question

Environment:

• OS: OSX 10.14
• Browser: Tested with Safari, Firefox.
• Library Version: Node 13.8, Leaflet 1.6, leaflet-ant-path 1.3.0, rollup 2.10.

I'm going to open a PR:

• [ ] yes
• [x ] no

Description: When I assemble a simple es6 script with rollup, ants don't craw! The display of the polyline remains static. Tried to resume() but no progress. Any idea?

Please clone this repo as a test case.

I don't know webpack. I'd be curious to see if a webpack build works. This may be a rollup issue.

Thanks for your help.

[devleaks]

Don't ask me why, but I noticed that <svg class="leaflet-ant-path"...> is missing an animation-duration attribute... If I add it (in the browser inspector), it crawls. :-) But why doesn't it get written when bundling with rollup?

[devleaks]

I tracked this one down. After I noticed some missing styles, I found the function that does attach them (_calculateAnimationSpeed). I looked at the generated code and found that for some obscure buggy reason, rollup strips the following piece of code from _calculateAnimationSpeed():

a = ["-webkit-", "-moz-", "-ms-", "-o-", ""]
    .map(function(t) {
        return "".concat(t, "animation-duration: ").concat(i);
    })
    .join(";");
Array.from(o, function(t) {
    (t.style.cssText = a), t.setAttribute("data-animated", "true");
});

If I add this piece of code in the rollup generated file, it works.