@stylistic/stylelint-plugin/lib/rules/selector-list-comma-newline-before/index.js

A collection of stylistic/formatting Stylelint rules

import stylelint from "stylelint"

import { addNamespace } from "../../utils/addNamespace/index.js"
import { getRuleDocUrl } from "../../utils/getRuleDocUrl/index.js"
import { selectorListCommaWhitespaceChecker } from "../../utils/selectorListCommaWhitespaceChecker/index.js"
import { whitespaceChecker } from "../../utils/whitespaceChecker/index.js"

let { utils: { ruleMessages, validateOptions } } = stylelint

let shortName = `selector-list-comma-newline-before`

export let ruleName = addNamespace(shortName)

export let messages = ruleMessages(ruleName, {
	expectedBefore: () => `Expected newline before ","`,
	expectedBeforeMultiLine: () => `Expected newline before "," in a multi-line list`,
	rejectedBeforeMultiLine: () => `Unexpected whitespace before "," in a multi-line list`,
})

export let meta = {
	url: getRuleDocUrl(shortName),
	fixable: true,
}

/** @type {import('stylelint').Rule} */
function rule (primary, _secondaryOptions, context) {
	let checker = whitespaceChecker(`newline`, primary, messages)

	return (root, result) => {
		let validOptions = validateOptions(result, ruleName, {
			actual: primary,
			possible: [`always`, `always-multi-line`, `never-multi-line`],
		})

		if (!validOptions) {
			return
		}

		/** @type {Map<import('postcss').Rule, number[]> | undefined} */
		let fixData

		selectorListCommaWhitespaceChecker({
			root,
			result,
			locationChecker: checker.beforeAllowingIndentation,
			checkedRuleName: ruleName,
			fix: (ruleNode, index) => {
				fixData = fixData || (new Map)

				let commaIndices = fixData.get(ruleNode) || []

				commaIndices.push(index)
				fixData.set(ruleNode, commaIndices)

				return true
			},
		})

		if (fixData) {
			for (let [ruleNode, commaIndices] of fixData.entries()) {
				let selector = ruleNode.raws.selector ? ruleNode.raws.selector.raw : ruleNode.selector

				for (let index of commaIndices.sort((a, b) => b - a)) {
					let beforeSelector = selector.slice(0, index)
					let afterSelector = selector.slice(index)

					if (primary.startsWith(`always`)) {
						let spaceIndex = beforeSelector.search(/\s+$/)

						beforeSelector = spaceIndex >= 0 ? beforeSelector.slice(0, spaceIndex) + context.newline + beforeSelector.slice(spaceIndex) : beforeSelector + context.newline
					} else if (primary === `never-multi-line`) {
						beforeSelector = beforeSelector.replace(/\s*$/, ``)
					}

					selector = beforeSelector + afterSelector
				}

				if (ruleNode.raws.selector) {
					ruleNode.raws.selector.raw = selector
				} else {
					ruleNode.selector = selector
				}
			}
		}
	}
}

rule.ruleName = ruleName
rule.messages = messages
rule.meta = meta

export default rule