From 92705b45454c75072417d383179d876833354c41 Mon Sep 17 00:00:00 2001
From: Roman Dvornov <rdvornov@gmail.com>
Date: Thu, 13 Jul 2017 01:03:03 +0300
Subject: [PATCH] refactoring of match result getTrace() method (25%
 performance boost)

---
 lib/lexer/trace.js | 31 ++++++++++++++++---------------
 test/lexer.js      |  2 +-
 2 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/lib/lexer/trace.js b/lib/lexer/trace.js
index 89fb534e..c52dad66 100644
--- a/lib/lexer/trace.js
+++ b/lib/lexer/trace.js
@@ -2,10 +2,12 @@ function getTrace(node) {
     function hasMatch(matchNode) {
         if (matchNode.type === 'ASTNode') {
             if (matchNode.node === node) {
+                result = [];
                 return true;
             }
 
             if (matchNode.childrenMatch) {
+                // use for-loop for better perfomance
                 for (var i = 0; i < matchNode.childrenMatch.length; i++) {
                     if (hasMatch(matchNode.childrenMatch[i])) {
                         return true;
@@ -13,30 +15,29 @@ function getTrace(node) {
                 }
             }
         } else {
-            var addToStack = matchNode.syntax.type === 'Type' ||
-                             matchNode.syntax.type === 'Property' ||
-                             matchNode.syntax.type === 'Keyword';
-
-            if (addToStack) {
-                stack.push(matchNode.syntax);
-            }
-
+            // use for-loop for better perfomance
             for (var i = 0; i < matchNode.match.length; i++) {
-                if (hasMatch(matchNode.match[i], node, stack)) {
+                if (hasMatch(matchNode.match[i])) {
+                    if (matchNode.syntax.type === 'Type' ||
+                        matchNode.syntax.type === 'Property' ||
+                        matchNode.syntax.type === 'Keyword') {
+                        result.unshift(matchNode.syntax);
+                    }
                     return true;
                 }
             }
-
-            if (addToStack) {
-                stack.pop();
-            }
         }
 
         return false;
     }
 
-    var stack = [];
-    return this.matched !== null && hasMatch(this.matched) ? stack : null;
+    var result = null;
+
+    if (this.matched !== null) {
+        hasMatch(this.matched);
+    }
+
+    return result;
 }
 
 function testNode(match, node, fn) {
diff --git a/test/lexer.js b/test/lexer.js
index 2c668d02..21c6bafa 100644
--- a/test/lexer.js
+++ b/test/lexer.js
@@ -267,7 +267,7 @@ describe('lexer', function() {
         var match = syntax.lexer.matchProperty('background', ast);
         var mismatch = syntax.lexer.matchProperty('margin', ast);
 
-        it('getNodeTrace', function() {
+        it('getTrace', function() {
             assert.deepEqual(match.getTrace(testNode), [
                 { type: 'Type', name: 'final-bg-layer' },
                 { type: 'Property', name: 'background-color' },