w3c / w3c/csswg-drafts

[css-cascade][css-transition] Should property aliasing/mapping applies to `transition[-property]`?

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Description

I would like to know in which cases a property name should be replaced in the parsing/serialization of transition-property. It does not seem clearly defined in CSS Cascade.

style.transitionProperty = `
  word-wrap,                /* Unprefixed legacy name alias */
  grid-row-gap,             /* Unprefixed legacy shorthand */
  page-break-before,        /* Unprefixed legacy shorthand */
  -webkit-background-size,  /* Legacy name alias */
  -webkit-box-ordinal-group /* Legacy mapping property */
`
style.cssText;

The output in Chrome for style.cssText is transition-property: word-wrap, grid-row-gap, page-break-before, -webkit-background-size, -webkit-box-ordinal-group;.

The output in Firefox is transition-property: overflow-wrap, row-gap, page-break-before, background-size, -moz-box-ordinal-group;.

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Research direction

Read the CSS Cascade aliasing section and the transition-property parsing and serialization rules. Compare the listed aliases and mappings with the Chrome and Firefox outputs in the issue, then document a clear normative rule for which names are replaced and how serialization should behave.

Written by the indexing model from the issue text.

Assessment

Tech stack
css
Domain
documentation
Issue type
Documentation
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
30/100

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