From a6943994a32bce6ad2c0e93d94aefd638aca5321 Mon Sep 17 00:00:00 2001
From: Dean Kerr <dean_k@live.co.uk>
Date: Wed, 23 Sep 2015 23:24:05 +0100
Subject: [PATCH] perf(core): prevent column set from being rebuilt each time
 data changes

Added guard to prevent column set being rebuilt and cell templates being
precompiled everytime grid data changes

Fixes #4386
---
 src/js/core/directives/ui-grid.js | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/js/core/directives/ui-grid.js b/src/js/core/directives/ui-grid.js
index d6e0d5eb0e..59871a52b0 100644
--- a/src/js/core/directives/ui-grid.js
+++ b/src/js/core/directives/ui-grid.js
@@ -91,9 +91,12 @@
         }
         
         if (newData) {
+          // columns length is greater than the number of row header columns, which don't count because they're created automatically
+          var hasColumns = self.grid.columns.length > (self.grid.rowHeaderColumns ? self.grid.rowHeaderColumns.length : 0);
+
           if (
-            // If we have no columns (i.e. columns length is either 0 or equal to the number of row header columns, which don't count because they're created automatically)
-            self.grid.columns.length === (self.grid.rowHeaderColumns ? self.grid.rowHeaderColumns.length : 0) &&
+            // If we have no columns
+            !hasColumns &&
             // ... and we don't have a ui-grid-columns attribute, which would define columns for us
             !$attrs.uiGridColumns &&
             // ... and we have no pre-defined columns
@@ -105,8 +108,8 @@
             self.grid.buildColumnDefsFromData(newData);
           }
 
-          // If we either have some columns defined, or some data defined
-          if (self.grid.options.columnDefs.length > 0 || newData.length > 0) {
+          // If we haven't built columns before and either have some columns defined or some data defined
+          if (!hasColumns && (self.grid.options.columnDefs.length > 0 || newData.length > 0)) {
             // Build the column set, then pre-compile the column cell templates
             promises.push(self.grid.buildColumns()
               .then(function() {