postcss-sorting/lib/properties-order/sortDeclarations.js

PostCSS plugin to keep rules and at-rules content in order.

const sortDeclarationsAlphabetically = require('./sortDeclarationsAlphabetically');
let vendor = require('./vendor');

module.exports = function sortDeclarations(a, b) {
	// If unprefixed prop names are the same, compare the prefixed versions
	if (a.node.type === 'decl' && b.node.type === 'decl' && a.unprefixedName === b.unprefixedName) {
		// If first property has no prefix and second property has prefix
		if (!vendor.prefix(a.name).length && vendor.prefix(b.name).length) {
			return 1;
		}

		if (vendor.prefix(a.name).length && !vendor.prefix(b.name).length) {
			return -1;
		}
	}

	if (a.orderData && b.orderData !== undefined) {
		// If a and b have the same group index, and a's property index is
		// higher than b's property index, in a sorted list a appears after
		// b:
		if (a.orderData.propertyIndex !== b.orderData.propertyIndex) {
			return a.orderData.propertyIndex - b.orderData.propertyIndex;
		}
	}

	if (
		a.unspecifiedPropertiesPosition === 'bottom' ||
		a.unspecifiedPropertiesPosition === 'bottomAlphabetical' ||
		b.unspecifiedPropertiesPosition === 'bottomAlphabetical'
	) {
		if (a.orderData !== undefined && b.orderData === undefined) {
			return -1;
		}

		if (a.orderData === undefined && b.orderData !== undefined) {
			return 1;
		}
	}

	if (a.unspecifiedPropertiesPosition === 'top') {
		if (a.orderData !== undefined && b.orderData === undefined) {
			return 1;
		}

		if (a.orderData === undefined && b.orderData !== undefined) {
			return -1;
		}
	}

	if (a.unspecifiedPropertiesPosition === 'bottomAlphabetical') {
		if (a.orderData === undefined && b.orderData === undefined) {
			return sortDeclarationsAlphabetically(a, b);
		}
	}

	// If a and b have the same group index and the same property index,
	// in a sorted list they appear in the same order they were in
	// original array:
	return a.initialIndex - b.initialIndex;
};