Fix Safari Download

[rlreamy]

Fix for issue #1227.

It appears that for Safari Version 14.0.1 (16610.2.11.51.8) the special code in fileSaver.js for handling Safari browsers is actually breaking the download. The filename is always "Unknown" and it doesn't download the entire image (in our case a scatter plot gave us only the axes and labels, but none of the points). Strangely a second try at the download will give the user the full plot, but the filename is still "Uknown".

Removing the special handling worked when testing with npm start.

[alexcjohnson]

Thanks @rlreamy - it's interesting that this works now, but it clearly didn't in past versions of Safari (and some docs haven't caught up yet, like https://www.w3schools.com/jsref/prop_anchor_download.asp still says "Not Supported")

Can we instead move the special handling after the if(canUseSaveLink) block? That way older versions that fail this test will still at least have the previous behavior.

[archmoj]

It would be really nice to get this PR to the finish line for the upcoming 2.1.0 release.
@rlreamy could you possibly address @alexcjohnson's comment above?

[rlreamy]

It is possible, but I cannot promise anything. This change was done as part of a work project, and I have not yet had time to revisit.
I can tell you that this change doesn't quite fix the issue, however. It does improve the situation, in that you will always get the correct filename now. However, there is a strange behavior that the first time you download the png, you get the axes, but not plot (for the scatter plots that we are generating with thousands of points). But, the second time on, it downloads everything as it should.
Another developer on my team will be revisiting this work in the next 2 weeks, and I will make sure to make a note of this request there.

[archmoj]

Thanks very much @rlreamy for the information.
It looks something we could fix in a patch release.
So for now I dropped it from v2.1.0 milestone.
I am looking forward to the follow up whenever you had time.

[archmoj]

💃 Thanks for the PR.
Merging into safari-download branch.