diff --git a/lib/lintPostcssResult.js b/lib/lintPostcssResult.js
new file mode 100644
index 0000000000..b3e8f8051b
--- /dev/null
+++ b/lib/lintPostcssResult.js
@@ -0,0 +1,142 @@
+'use strict';
+
+const assignDisabledRanges = require('./assignDisabledRanges');
+const get = require('lodash/get');
+const getOsEol = require('./utils/getOsEol');
+const reportUnknownRuleNames = require('./reportUnknownRuleNames');
+const rulesOrder = require('./rules');
+
+/** @typedef {import('stylelint').StylelintStandaloneOptions} StylelintStandaloneOptions */
+/** @typedef {import('stylelint').PostcssResult} PostcssResult */
+/** @typedef {import('stylelint').StylelintConfig} StylelintConfig */
+
+/**
+ * @param {StylelintStandaloneOptions} stylelintOptions
+ * @param {PostcssResult} postcssResult
+ * @param {StylelintConfig} config
+ * @returns {Promise<any>}
+ */
+function lintPostcssResult(stylelintOptions, postcssResult, config) {
+	postcssResult.stylelint.ruleSeverities = {};
+	postcssResult.stylelint.customMessages = {};
+	postcssResult.stylelint.stylelintError = false;
+	postcssResult.stylelint.quiet = config.quiet;
+	postcssResult.stylelint.config = config;
+
+	/** @type {string} */
+	let newline;
+	const postcssDoc = postcssResult.root;
+
+	if (postcssDoc) {
+		if (!('type' in postcssDoc)) {
+			throw new Error('Unexpected Postcss root object!');
+		}
+
+		// @ts-ignore TODO TYPES property css does not exists
+		const newlineMatch = postcssDoc.source && postcssDoc.source.input.css.match(/\r?\n/);
+
+		newline = newlineMatch ? newlineMatch[0] : getOsEol();
+
+		assignDisabledRanges(postcssDoc, postcssResult);
+	}
+
+	if (stylelintOptions.ignoreDisables) {
+		postcssResult.stylelint.ignoreDisables = true;
+	}
+
+	if (stylelintOptions.reportNeedlessDisables) {
+		postcssResult.stylelint.reportNeedlessDisables = true;
+	}
+
+	const isFileFixCompatible = isFixCompatible(postcssResult);
+
+	if (!isFileFixCompatible) {
+		postcssResult.stylelint.disableWritingFix = true;
+	}
+
+	const postcssRoots = /** @type {import('postcss').Root[]} */ (postcssDoc &&
+	postcssDoc.constructor.name === 'Document'
+		? postcssDoc.nodes
+		: [postcssDoc]);
+
+	// Promises for the rules. Although the rule code runs synchronously now,
+	// the use of Promises makes it compatible with the possibility of async
+	// rules down the line.
+	/** @type {Array<Promise<any>>} */
+	const performRules = [];
+
+	const rules = config.rules
+		? Object.keys(config.rules).sort(
+				(a, b) => Object.keys(rulesOrder).indexOf(a) - Object.keys(rulesOrder).indexOf(b),
+		  )
+		: [];
+
+	rules.forEach((ruleName) => {
+		const ruleFunction = rulesOrder[ruleName] || get(config, ['pluginFunctions', ruleName]);
+
+		if (ruleFunction === undefined) {
+			performRules.push(
+				Promise.all(
+					postcssRoots.map((postcssRoot) =>
+						reportUnknownRuleNames(ruleName, postcssRoot, postcssResult),
+					),
+				),
+			);
+
+			return;
+		}
+
+		const ruleSettings = get(config, ['rules', ruleName]);
+
+		if (ruleSettings === null || ruleSettings[0] === null) {
+			return;
+		}
+
+		const primaryOption = ruleSettings[0];
+		const secondaryOptions = ruleSettings[1];
+
+		// Log the rule's severity in the PostCSS result
+		const defaultSeverity = config.defaultSeverity || 'error';
+
+		postcssResult.stylelint.ruleSeverities[ruleName] = get(
+			secondaryOptions,
+			'severity',
+			defaultSeverity,
+		);
+		postcssResult.stylelint.customMessages[ruleName] = get(secondaryOptions, 'message');
+
+		performRules.push(
+			Promise.all(
+				postcssRoots.map((postcssRoot) =>
+					ruleFunction(primaryOption, secondaryOptions, {
+						fix:
+							stylelintOptions.fix &&
+							// Next two conditionals are temporary measures until #2643 is resolved
+							isFileFixCompatible &&
+							!postcssResult.stylelint.disabledRanges[ruleName],
+						newline,
+					})(postcssRoot, postcssResult),
+				),
+			),
+		);
+	});
+
+	return Promise.all(performRules);
+}
+
+/**
+ * There are currently some bugs in the autofixer of Stylelint.
+ * The autofixer does not yet adhere to stylelint-disable comments, so if there are disabled
+ * ranges we can not autofix this document. More info in issue #2643.
+ *
+ * @param {PostcssResult} postcssResult
+ * @returns {boolean}
+ */
+function isFixCompatible({ stylelint }) {
+	// Check for issue #2643
+	if (stylelint.disabledRanges.all.length) return false;
+
+	return true;
+}
+
+module.exports = lintPostcssResult;
diff --git a/lib/lintSource.js b/lib/lintSource.js
index 4c38ac96ec..f5bc8f3df4 100644
--- a/lib/lintSource.js
+++ b/lib/lintSource.js
@@ -1,16 +1,13 @@
 'use strict';
 
-const _ = require('lodash');
-const assignDisabledRanges = require('./assignDisabledRanges');
-const getOsEol = require('./utils/getOsEol');
+const lintPostcssResult = require('./lintPostcssResult');
 const path = require('path');
-const reportUnknownRuleNames = require('./reportUnknownRuleNames');
-const rulesOrder = require('./rules');
 
 /** @typedef {import('stylelint').StylelintInternalApi} StylelintInternalApi */
+/** @typedef {import('stylelint').GetLintSourceOptions} Options */
+/** @typedef {import('postcss').Result} Result */
 /** @typedef {import('stylelint').PostcssResult} PostcssResult */
 /** @typedef {import('stylelint').StylelintPostcssResult} StylelintPostcssResult */
-/** @typedef {import('stylelint').GetLintSourceOptions} Options */
 
 /**
  * Run stylelint on a PostCSS Result, either one that is provided
@@ -84,7 +81,7 @@ module.exports = function lintSource(stylelint, options = {}) {
 					stylelint: stylelintResult,
 				});
 
-				return lintPostcssResult(stylelint, stylelintPostcssResult, config).then(
+				return lintPostcssResult(stylelint._options, stylelintPostcssResult, config).then(
 					() => stylelintPostcssResult,
 				);
 			}
@@ -101,7 +98,7 @@ module.exports = function lintSource(stylelint, options = {}) {
 						stylelint: stylelintResult,
 					});
 
-					return lintPostcssResult(stylelint, stylelintPostcssResult, config).then(
+					return lintPostcssResult(stylelint._options, stylelintPostcssResult, config).then(
 						() => stylelintPostcssResult,
 					);
 				});
@@ -109,120 +106,6 @@ module.exports = function lintSource(stylelint, options = {}) {
 	});
 };
 
-/**
- * @param {StylelintInternalApi} stylelint
- * @param {PostcssResult} postcssResult
- * @param {import('stylelint').StylelintConfig} config
- * @returns {Promise<any>}
- */
-function lintPostcssResult(stylelint, postcssResult, config) {
-	postcssResult.stylelint.ruleSeverities = {};
-	postcssResult.stylelint.customMessages = {};
-	postcssResult.stylelint.stylelintError = false;
-	postcssResult.stylelint.quiet = config.quiet;
-	postcssResult.stylelint.config = config;
-
-	/** @type {string} */
-	let newline;
-	const postcssDoc = postcssResult.root;
-
-	if (postcssDoc) {
-		if (!('type' in postcssDoc)) {
-			throw new Error('Unexpected Postcss root object!');
-		}
-
-		// @ts-ignore TODO TYPES property css does not exists
-		const newlineMatch = postcssDoc.source && postcssDoc.source.input.css.match(/\r?\n/);
-
-		newline = newlineMatch ? newlineMatch[0] : getOsEol();
-
-		assignDisabledRanges(postcssDoc, postcssResult);
-	}
-
-	if (stylelint._options.ignoreDisables) {
-		postcssResult.stylelint.ignoreDisables = true;
-	}
-
-	if (stylelint._options.reportNeedlessDisables) {
-		postcssResult.stylelint.reportNeedlessDisables = true;
-	}
-
-	const isFileFixCompatible = isFixCompatible(postcssResult);
-
-	if (!isFileFixCompatible) {
-		postcssResult.stylelint.disableWritingFix = true;
-	}
-
-	const postcssRoots = /** @type {import('postcss').Root[]} */ (postcssDoc &&
-	postcssDoc.constructor.name === 'Document'
-		? postcssDoc.nodes
-		: [postcssDoc]);
-
-	// Promises for the rules. Although the rule code runs synchronously now,
-	// the use of Promises makes it compatible with the possibility of async
-	// rules down the line.
-	/** @type {Array<Promise<any>>} */
-	const performRules = [];
-
-	const rules = config.rules
-		? Object.keys(config.rules).sort(
-				(a, b) => Object.keys(rulesOrder).indexOf(a) - Object.keys(rulesOrder).indexOf(b),
-		  )
-		: [];
-
-	rules.forEach((ruleName) => {
-		const ruleFunction = rulesOrder[ruleName] || _.get(config, ['pluginFunctions', ruleName]);
-
-		if (ruleFunction === undefined) {
-			performRules.push(
-				Promise.all(
-					postcssRoots.map((postcssRoot) =>
-						reportUnknownRuleNames(ruleName, postcssRoot, postcssResult),
-					),
-				),
-			);
-
-			return;
-		}
-
-		const ruleSettings = _.get(config, ['rules', ruleName]);
-
-		if (ruleSettings === null || ruleSettings[0] === null) {
-			return;
-		}
-
-		const primaryOption = ruleSettings[0];
-		const secondaryOptions = ruleSettings[1];
-
-		// Log the rule's severity in the PostCSS result
-		const defaultSeverity = config.defaultSeverity || 'error';
-
-		postcssResult.stylelint.ruleSeverities[ruleName] = _.get(
-			secondaryOptions,
-			'severity',
-			defaultSeverity,
-		);
-		postcssResult.stylelint.customMessages[ruleName] = _.get(secondaryOptions, 'message');
-
-		performRules.push(
-			Promise.all(
-				postcssRoots.map((postcssRoot) =>
-					ruleFunction(primaryOption, secondaryOptions, {
-						fix:
-							stylelint._options.fix &&
-							// Next two conditionals are temporary measures until #2643 is resolved
-							isFileFixCompatible &&
-							!postcssResult.stylelint.disabledRanges[ruleName],
-						newline,
-					})(postcssRoot, postcssResult),
-				),
-			),
-		);
-	});
-
-	return Promise.all(performRules);
-}
-
 /**
  * @returns {StylelintPostcssResult}
  */
@@ -253,18 +136,3 @@ function createEmptyPostcssResult(filePath) {
 		warn: () => {},
 	};
 }
-
-/**
- * There are currently some bugs in the autofixer of Stylelint.
- * The autofixer does not yet adhere to stylelint-disable comments, so if there are disabled
- * ranges we can not autofix this document. More info in issue #2643.
- *
- * @param {PostcssResult} postcssResult
- * @returns {boolean}
- */
-function isFixCompatible({ stylelint }) {
-	// Check for issue #2643
-	if (stylelint.disabledRanges.all.length) return false;
-
-	return true;
-}