fix(ngRepeat): improve errors for duplicate items

smilli · btford · commit 1812af58c2d4 · 2014-08-29T13:54:57.000-07:00
-Log the value that had the duplicate key, as well as the key
The error that is thrown when items have duplicate track by keys can be
confusing because only the duplicate key is logged.  If the user didn't
provide that key themselves, they may not know what it is or what item
it corresponds to.
diff --git a/src/ng/directive/ngRepeat.js b/src/ng/directive/ngRepeat.js
@@ -309,8 +309,9 @@ var ngRepeatDirective = ['$parse', '$animate', function($parse, $animate) {
                if (block && block.scope) lastBlockMap[block.id] = block;
              });
              // This is a duplicate and we need to throw an error
-             throw ngRepeatMinErr('dupes', "Duplicates in a repeater are not allowed. Use 'track by' expression to specify unique keys. Repeater: {0}, Duplicate key: {1}",
-                                                                                                                                                    expression,       trackById);
+             throw ngRepeatMinErr('dupes',
+                  "Duplicates in a repeater are not allowed. Use 'track by' expression to specify unique keys. Repeater: {0}, Duplicate key: {1}, Duplicate value: {2}",
+                  expression, trackById, toJson(value));
            } else {
              // new never before seen block
              nextBlockOrder[index] = { id: trackById };
diff --git a/test/ng/directive/ngRepeatSpec.js b/test/ng/directive/ngRepeatSpec.js
@@ -940,7 +940,8 @@ describe('ngRepeat', function() {
       scope.items = [a, a, a];
       scope.$digest();
       expect($exceptionHandler.errors.shift().message).
-          toMatch(/^\[ngRepeat:dupes\] Duplicates in a repeater are not allowed\. Use 'track by' expression to specify unique keys\. Repeater: item in items, Duplicate key: object:003/);
+          toMatch(
+            /^\[ngRepeat:dupes\] Duplicates in a repeater are not allowed\. Use 'track by' expression to specify unique keys\. Repeater: item in items, Duplicate key: object:003, Duplicate value: {}/);
 
       // recover
       scope.items = [a];
@@ -960,7 +961,8 @@ describe('ngRepeat', function() {
       scope.items = [d, d, d];
       scope.$digest();
       expect($exceptionHandler.errors.shift().message).
-          toMatch(/^\[ngRepeat:dupes\] Duplicates in a repeater are not allowed\. Use 'track by' expression to specify unique keys\. Repeater: item in items, Duplicate key: object:009/);
+          toMatch(
+            /^\[ngRepeat:dupes\] Duplicates in a repeater are not allowed\. Use 'track by' expression to specify unique keys\. Repeater: item in items, Duplicate key: object:009, Duplicate value: {}/);
 
       // recover
       scope.items = [a];
