add html handling in native types

[maxired]

This PR solves #2928 and allows to drag and drop HTML elements such as images from another tab.

This PR does not implements any custom logic to deal with the HTML data in itself.

[codecov]

Codecov Report

Merging #2949 (5762f72) into main (cab86e2) will decrease coverage by 0.01%.
The diff coverage is 33.33%.

@@            Coverage Diff             @@
##             main    #2949      +/-   ##
==========================================
- Coverage   46.96%   46.94%   -0.02%     
==========================================
  Files          79       79              
  Lines        2291     2294       +3     
  Branches      501      501              
==========================================
+ Hits         1076     1077       +1     
- Misses       1215     1217       +2     

Impacted Files	Coverage Δ
packages/backend-html5/src/HTML5BackendImpl.ts	20.52% <0.00%> (-0.07%)	⬇️
...d-html5/src/NativeDragSources/nativeTypesConfig.ts	16.66% <0.00%> (-3.34%)	⬇️
packages/backend-html5/src/NativeTypes.ts	100.00% <100.00%> (ø)

[maxired]

@darthtrevino do you have any opinion about this ?

[darthtrevino]

I apologize, I've been a beet slammed at work. Just taking a quick look - Is the preventDefault() necessary()? At some point we removed some of that because we didn't want to interfere with custom handling of native events. Also, can you put together an example on the docsite using this new type? You can base it off of the existing native types example or just extend it if you prefer

[maxired]

Thanks for your answer. Yes I will try to setup an example.

Without the preventDefault, the browser opens the content in a new tab in that case. I am not very familiar with this code base, so maybe it can be put somewhere else? As a side not, I did not saw side effects on other handlers.

[maxired]

@darthtrevino I've just added an example, please let me know if this looks good to you.

[maxired]

@darthtrevino sorry to bother you. What is the status on this one ?

[darthtrevino]

Hey Maxence, Again, apologies for the delay. I went ahead and merged it, I'll work on stabilizing the main branch and preparing for a release.

…

On Tue, Feb 9, 2021 at 10:47 AM Maxence Dalmais ***@***.***> wrote: @darthtrevino <https://github.com/darthtrevino> sorry to bother you. What is the status on this one ? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#2949 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAA3XCCGEQS6ME57NBF6TRLS6F7LLANCNFSM4VV2OZWA> .

[inukshuk]

This PR raises a problem: dragged images, URLs, and links etc. typically have multiple data transfer items with type text/html and text/uri-list and even text/plain. Right now it seems that matchNativeItemType returns just the first match: that means for example that dragged images or URLs are now only matched as type HTML, because it was added higher up in the native types config. For this reason, this PR makes it impossible (I believe?) to register drop targets for URLs -- unless you register for type HTML and then parse out the URL from the HTML data.