No-Comma Color Functions in CSS

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Chris Coyier on

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There have been a couple of viral tweets about this lately, one from Adam Argyle and one from Mathias Bynes. This is a nice change that makes CSS a bit more clear. Before, every single color function actually needs two functions, one for transparency and one without, this eliminates that need and brings the syntax more-inline with CSS grammar overall.

Lemme remake the code blocks from Mathias’ tweet here:

/* Old Syntax */
rgb(0, 128, 255)

rgba(0, 128, 255, 0.5)

hsl(198, 38% 50%)

hsla(198, 28%, 50%, 0.5)
/* New Syntax */
rgb(0 128 255)

rgb(0 128 255 / 50%)

hsl(198deg 28% 50%)

hsl(198deg 28% 50% / 50%)

lab(56.29% -10.93 16.58 / 50%)

lch(56.29% 19.86 236.62 / 50%)

color(sRGB 0 0.50 1 / 50%)

Thought party:

  • The browser support is pretty good: everything but IE 11.
  • If you need IE 11 support, you can preprocess it (or not use it). PostCSS’s preset-env does it as well as the very specific plugin postcss-color-rgb (weird it doesn’t do HSL also).
  • If you don’t like it, you literally never need to use it. No browser will ever pull support for such an important feature.
  • The reason to switch is muscle memory and consistent-looking codebases as new color functions (e.g, lab, lch, and color) will only support this new syntax.
  • There is a weird hybrid between old and new. You can pass an opacity value to rgb() and it still works like rgb(255, 0, 0, 0.5);.
  • If you need it in Sass (which is apparently a pain to support), there is a weird workaround. I would guess Sass will get around to supporting it. If they can’t, this is the kind of barb that drives people away from projects.
  • Prettier, which is in the business of cleaning up your code from the perspective of spacing and syntax, could intervene here and convert syntax, but it’s not going to (the Prettier stance is to not change the AST).
  • I imagine DevTools will start showing colors in this format, which will drive adoption.
  • Remember even hex code colors have a fancy new format.