🧱 Incorrect font destructuring

[bartveneman]

From cssday.nl

body {
  font: 100% Source Code Pro, Inconsolata, Menlo, monospace;
}

Expected:

• font-size: 100%
• font-family: Source Code Pro, Inconsolata, Menlo, monospace

Actual:

• font-size: Code
• font-family: Pro, Inconsolata, Menlo, monospace

The font-family isn't quoted, to the individual parts of Source Code Pro end up being Identifier, which messes with our algorithm.

[bartveneman]

Related to https://github.com/projectwallace/css-analyzer/issues/321 because of our whacky font destructuring algorithm.

[bartveneman]

Example from exaprint.fr:

font: Styrene A,sans-serif;

produces a font-size -> Styrene and a fontFamily -> A,sans-serif

[bartveneman]

from cssday.nl

font: 100% source code pro, inconsolata, menlo, monospace

reports as font-size: code

[bartveneman]

See Twitter thread here https://twitter.com/csstree/status/1632496974921342976

See “Syntax matching” in usage section of readme https://github.com/csstree/csstree#usage It also should work with string values beside of AST nodes.

[bartveneman]

Using CSSTree's syntax matching to destructure a font shorthand:

import * as csstree from 'css-tree'
let fonts = [
	'1em / 2px sans-serif, "Test me"',
	'100% Source Code Pro, Inconsolata, Menlo, monospace',
	// 'Styrene A, sans-serif',
	'400 1em -apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji"',
	// '14px/1 var(--font-sans)',
]

for (let font of fonts) {
	let ast = csstree.parse(font, { context: 'value' })
	let matchResult = csstree.lexer.matchProperty('font', ast)
	console.log(font)
	console.log(JSON.stringify(matchResult.matched.match, null, 2))
}

// 1em / 2px sans-serif, "Test me"
// [
//   {
//     syntax: { type: 'Property', name: 'font-size' },
//     match: [ [Object] ]
//   },
//   {
//     syntax: { type: 'Token', value: '/' },
//     token: '/',
//     node: { type: 'Operator', loc: null, value: '/' }
//   },
//   {
//     syntax: { type: 'Property', name: 'line-height' },
//     match: [ [Object] ]
//   },
//   {
//     syntax: { type: 'Property', name: 'font-family' },
//     match: [ [Object], [Object], [Object] ]
//   }
// ]

But it errors when mixing with var()