Make font destructuring more reliable

[bartveneman]

CSSTree has syntax matching which is really reliable and saves a lot of code. It might be a bit slower on the runtime, but that's probably worth it.

csstree.walk(ast, function (node) {
	if (node.type == 'Declaration' && node.property == 'font') {
		console.log(destructure(node, s))
	}
})

function destructure(node, s) {
	if (
		node.value.children.size == 1 &&
		node.value.children.first.type == 'Identifier'
	) {
		return { keyword: node.value.children.first.name }
	}

	let matchResult = csstree.lexer.matchProperty('font', node.value)
	let line_height
	let font_size
	let font_family = [0, 0]

	node.value.children.forEach(function (child) {
		if (matchResult.isProperty(child, 'font-size')) {
			font_size = s(child)
		} else if (matchResult.isProperty(child, 'line-height')) {
			line_height = s(child)
		} else if (matchResult.isProperty(child, 'font-family')) {
			if (!font_family[0]) {
				font_family[0] = child.loc.start.offset
			}
			let end = child.loc.end.offset
			let offset_end = font_family[1]
			if (end > offset_end) {
				font_family[1] = end
			}
		}
	})

	return {
		font_family: css.substring(font_family[0], font_family[1]),
		font_size,
		line_height,
	}
}

[bartveneman]

Build (before):

Build "@projectwallace/css-analyzer" to dist:
      6.12 kB: analyzer.cjs.gz
      5.48 kB: analyzer.cjs.br
      5.61 kB: analyzer.modern.js.gz
      5.05 kB: analyzer.modern.js.br
      6.09 kB: analyzer.module.js.gz
      5.47 kB: analyzer.module.js.br
      6.21 kB: analyzer.umd.js.gz
      5.58 kB: analyzer.umd.js.br

After:

Build "@projectwallace/css-analyzer" to dist:
      5.95 kB: analyzer.cjs.gz
      5.38 kB: analyzer.cjs.br
      5.32 kB: analyzer.modern.js.gz
      4.81 kB: analyzer.modern.js.br
      5.81 kB: analyzer.module.js.gz
      5.21 kB: analyzer.module.js.br
      6.06 kB: analyzer.umd.js.gz
      5.44 kB: analyzer.umd.js.br