v2.0.0-rc.0

Check out the Pre-Release Announcement on our community forum for details about this Release Candidate

Our commitment to semantic versioning requires us to make this next release a major version bump because we are making some backwards-incompatible changes to older and deprecated features (see below), but we see this as a low-risk maintenance release and we expect that the vast majority of users should plan to upgrade without fearing significant issues, including Javascript developers who embed Plotly.js directly in their apps or websites, as well as data scientists using Plotly.js via Plotly.py in a notebook environment, and of course Dash app developers!

Added

• CSP safety: refactored to avoid usage of function constructors from basic, cartesian, finance, geo, and mapbox
  partial bundles and added tests to ensure that they will not again do so in the future [#5359, #5383, #5387],
  with thanks to Equinor for sponsoring the related development!
• Add strict partial bundle [#5413, #5444], which includes
  the maximal subset of the library which does not rely on function constructors
• Implement "fast" zsmooth option for image trace [#5354, #5386],
  with thanks to @almarklein for the contribution!

Removed

• Drop support for old browsers IE9 and IE10 [#5376, #5380, #5460]
• Stop exporting v3 of d3 under Plotly.d3 [#5400, #5406]
• Stop attaching _has* plot types to fullLayout [#5409]
• Reduce the number of exported methods from Plotly.Fx and Plotly.Plots in the API [#5420]
• Drop Plotly.plot from the API [#5412, #5370, #5393]
• Drop Plotly.Queue from the API [#5423]
• Drop non-object role keys from attribute definition [#5425, #5432]
• Drop deprecated contourgl and area traces as well as deprecated legacy
  pre-scatterpolar polar-related attributes bar.t, bar.r,
  scatter.t, scatter.r, layout.radialaxis, layout.angularaxis and
  gd.framework [#5399, #5408, #5409, #5398, #5438]

Deprecated

• Deprecate heatmapgl and pointcloud trace types for later removal [#5447]

Changed

• Add major versions e.g. "latest-v2" when publishing latest to CDN and keep "latest" for v1 [#5462]
• Switch to native-promise-only module to handle es6 promises [#5358]
• Switch to probe-image-size module to get width and height of images [#5388]
• Relax test for plain objects to enable validation in node.js and multiple window contexts [#5411]
• Fire plotly_unhover event when dragging [#5407],
  with thanks to @rreusser for the contribution!
• Include transforms and calendars in partial bundles [#5379, #5422]
• Require unminified mapbox-gl dependency for unminified bundles and
  revisit compression options for minified bundles [#5449]
• Remove header comments from the source files and only add headers to the top of
  dist files at build time [#5436, #5446]
• Guard against unexpected characters at build time [#5424]
• More maintenance work listed under the the 60th milestone!

Fixed

• Fix "toself" fill for scattergl traces to handle multiple polygons [#5355],
  with thanks to @ruijin for the contribution!
• Fix element targeting on hover in shadow DOM [#5256],
  with thanks to @dbluhm for the contribution!
• Fix displaying zero threshold for indicator trace [#5430]
• Avoid duplicate keys in object literals within plotly builds [#5458]
• Improve attribute compression and avoid redundant copyright comments in non-minified
  bundles [#5426, #5429, #5439]