From 1839cbaffa5ad33ac6bfc66a393a31ba880ca8c6 Mon Sep 17 00:00:00 2001
From: The Jared Wilcurt <TheJaredWilcurt@users.noreply.github.com>
Date: Sat, 26 Dec 2020 17:08:45 -0500
Subject: [PATCH] Remove Identical Properties

---
 src/css.js            | 22 +++++++++++++++++++++-
 test/out.json         |  1 -
 tests/src/css.test.js | 23 +++++++++++++++++++++++
 3 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/src/css.js b/src/css.js
index 13968c6..43edf91 100644
--- a/src/css.js
+++ b/src/css.js
@@ -4,6 +4,23 @@ const cssUglifier = require('./css-uglifier.js');
 const encodeClassName = require('./css-class-encoding.js');
 const helpers = require('./helpers.js');
 
+/**
+ * Remove duplicate property/value pairs that are duplicates.
+ * `display: none; display: none;` becomes `display:none;`
+ * `display: block; display: none;` is unchanged because they
+ * are not identical.
+ *
+ * @param  {object} classMap  The class map object used by the HTML/JSON
+ * @return {object}           Returns the classMap object
+ */
+function removeIdenticalProperties (classMap) {
+  // Remove identical properties
+  Object.keys(classMap).forEach(function (selector) {
+    classMap[selector] = Array.from(new Set(classMap[selector].reverse())).reverse();
+  });
+  return classMap;
+}
+
 const css = function (options, input, uglify) {
   options = options || {};
   input = input || '';
@@ -30,7 +47,7 @@ const css = function (options, input, uglify) {
     }
   };
 
-  const classMap = {};
+  let classMap = {};
   const newRules = {};
 
   /* A rule looks like:
@@ -139,6 +156,8 @@ const css = function (options, input, uglify) {
     });
   });
 
+  classMap = removeIdenticalProperties(classMap);
+
   if (uglify) {
     let index = 0;
     Object.keys(newRules).forEach(function (key) {
@@ -176,4 +195,5 @@ const css = function (options, input, uglify) {
   };
 };
 
+css.removeIdenticalProperties = removeIdenticalProperties;
 module.exports = css;
diff --git a/test/out.json b/test/out.json
index 7039afa..22bbea3 100644
--- a/test/out.json
+++ b/test/out.json
@@ -10,7 +10,6 @@
     ".rp__display__--COLONblock",
     ".rp__display__--COLONinline-block",
     ".rp__vertical-align__--COLONbaseline",
-    ".rp__display__--COLONnone",
     ".rp__height__--COLON0",
     ".rp__display__--COLONnone",
     ".rp__background__--COLONtransparent",
diff --git a/tests/src/css.test.js b/tests/src/css.test.js
index b8b8715..94253de 100644
--- a/tests/src/css.test.js
+++ b/tests/src/css.test.js
@@ -14,6 +14,29 @@ describe('CSS', () => {
     };
   });
 
+  describe('removeIdenticalProperties', () => {
+    test('Removes dupes', () => {
+      expect(css.removeIdenticalProperties({
+        '.duplicates': [
+          '.rp__display__--COLONnone',
+          '.rp__display__--COLONblock',
+          '.rp__display__--COLONnone',
+          '.rp__display__--COLONinline-block',
+          '.rp__display__--COLONnone',
+          '.rp__display__--COLONflex'
+        ]
+      }))
+        .toEqual({
+          '.duplicates': [
+            '.rp__display__--COLONblock',
+            '.rp__display__--COLONinline-block',
+            '.rp__display__--COLONnone',
+            '.rp__display__--COLONflex'
+          ]
+        });
+    });
+  });
+
   describe('Bad inputs', () => {
     test('Empty', () => {
       expect(css())