From 121acce9a731ef549c62a140083235e65dfd3dfe Mon Sep 17 00:00:00 2001
From: Fedya Petrakov <jakephin2015@gmail.com>
Date: Wed, 28 Dec 2022 19:13:48 +0300
Subject: [PATCH] Refactor declaration-block-no-duplicate-properties (#6545)

---
 .../index.js                                  | 142 ++++++------------
 1 file changed, 48 insertions(+), 94 deletions(-)

diff --git a/lib/rules/declaration-block-no-duplicate-properties/index.js b/lib/rules/declaration-block-no-duplicate-properties/index.js
index 31a70524e0..cb755c1d64 100644
--- a/lib/rules/declaration-block-no-duplicate-properties/index.js
+++ b/lib/rules/declaration-block-no-duplicate-properties/index.js
@@ -88,97 +88,58 @@ const rule = (primary, secondaryOptions, context) => {
 
 				const indexDuplicate = decls.findIndex((d) => d.prop.toLowerCase() === lowerProp);
 
-				if (indexDuplicate !== -1) {
-					const duplicateDecl = decls[indexDuplicate];
-					const duplicateValue = duplicateDecl ? duplicateDecl.value : '';
-					const duplicateImportant = duplicateDecl ? duplicateDecl.important : false;
-
-					if (ignoreDiffValues || ignorePrefixlessSameValues) {
-						// fails if duplicates are not consecutive
-						if (indexDuplicate !== decls.length - 1) {
-							if (context.fix) {
-								if (!important && duplicateImportant) {
-									decl.remove();
-								} else {
-									removePreviousDuplicate(decls, lowerProp);
-								}
-
-								return;
-							}
-
-							report({
-								message: messages.rejected(prop),
-								node: decl,
-								result,
-								ruleName,
-								word: prop,
-							});
-
-							return;
-						}
-
-						if (ignorePrefixlessSameValues) {
-							// fails if values of consecutive, unprefixed duplicates are equal
-							if (vendor.unprefixed(value) !== vendor.unprefixed(duplicateValue)) {
-								if (context.fix) {
-									if (!important && duplicateImportant) {
-										decl.remove();
-									} else {
-										removePreviousDuplicate(decls, lowerProp);
-									}
-
-									return;
-								}
-
-								report({
-									message: messages.rejected(prop),
-									node: decl,
-									result,
-									ruleName,
-									word: prop,
-								});
-
-								return;
-							}
-						}
-
-						// fails if values of consecutive duplicates are equal
-						if (value === duplicateValue) {
-							if (context.fix) {
-								removePreviousDuplicate(decls, lowerProp);
-
-								return;
-							}
-
-							report({
-								message: messages.rejected(prop),
-								node: decl,
-								result,
-								ruleName,
-								word: prop,
-							});
-
-							return;
-						}
+				if (indexDuplicate === -1) {
+					decls.push(decl);
+				}
 
-						return;
+				const duplicateDecl = decls[indexDuplicate];
+
+				if (!duplicateDecl) {
+					return;
+				}
+
+				const duplicateValue = duplicateDecl.value || '';
+				const duplicateImportant = duplicateDecl.important || false;
+				const duplicateIsMoreImportant = !important && duplicateImportant;
+				const duplicatesAreConsecutive = indexDuplicate === decls.length - 1;
+				const unprefixedDuplicatesAreEqual =
+					vendor.unprefixed(value) === vendor.unprefixed(duplicateValue);
+
+				const fixOrReport = () => {
+					if (!context.fix) {
+						return report({
+							message: messages.rejected(prop),
+							node: decl,
+							result,
+							ruleName,
+							word: prop,
+						});
 					}
 
-					if (ignoreDuplicates && indexDuplicate === decls.length - 1) {
-						return;
+					if (duplicateIsMoreImportant) {
+						return decl.remove();
 					}
 
-					if (context.fix) {
-						if (!important && duplicateImportant) {
-							decl.remove();
-						} else {
-							removePreviousDuplicate(decls, lowerProp);
-						}
+					return duplicateDecl.remove();
+				};
+
+				if (ignoreDiffValues || ignorePrefixlessSameValues) {
+					if (
+						!duplicatesAreConsecutive ||
+						(ignorePrefixlessSameValues && !unprefixedDuplicatesAreEqual)
+					) {
+						fixOrReport();
+					}
 
+					if (value !== duplicateValue) {
 						return;
 					}
 
-					report({
+					if (context.fix) {
+						return duplicateDecl.remove();
+					}
+
+					return report({
 						message: messages.rejected(prop),
 						node: decl,
 						result,
@@ -187,23 +148,16 @@ const rule = (primary, secondaryOptions, context) => {
 					});
 				}
 
-				decls.push(decl);
+				if (ignoreDuplicates && duplicatesAreConsecutive) {
+					return;
+				}
+
+				fixOrReport();
 			});
 		});
 	};
 };
 
-/**
- * @param {import('postcss').Declaration[]} declarations
- * @param {string} lowerProperty
- * @returns {void}
- * */
-function removePreviousDuplicate(declarations, lowerProperty) {
-	const declToRemove = declarations.find((d) => d.prop.toLowerCase() === lowerProperty);
-
-	if (declToRemove) declToRemove.remove();
-}
-
 rule.ruleName = ruleName;
 rule.messages = messages;
 rule.meta = meta;