From 5796bd77d6de3bb09a83bd0ed553b6475a8642bd Mon Sep 17 00:00:00 2001
From: Slava Kim <slava@meteor.com>
Date: Mon, 26 Jan 2015 15:02:42 -0800
Subject: [PATCH]  #each .. in extends the data context for children

Regular #each ({{#each items}}) sets a new data context for each child view to
the item of the sequence.

The new #each ({{#each item in items}}) preserves the data context and extends
it to have the variable like 'item'
---
 packages/blaze/builtins.js | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/packages/blaze/builtins.js b/packages/blaze/builtins.js
index fc03136c0d..a92f273cd9 100644
--- a/packages/blaze/builtins.js
+++ b/packages/blaze/builtins.js
@@ -112,19 +112,20 @@ Blaze.Each = function (argFunc, contentFunc, elseFunc) {
     }, {
       addedAt: function (id, item, index) {
         Tracker.nonreactive(function () {
-          // create an alias for the data context defined by argFunc.
+          var newDataContext;
           if (eachView.variableName) {
+            // new-style #each (as in {{#each item in items}})
+            // the new data context is the same but with an extension by
+            // variable name (e.g. 'item')
             var _item = item;
-            if (! _.isObject(item)) {
-              item = {};
-            } else {
-              item = _.clone(item);
-            }
-
-            item[eachView.variableName] = _item;
+            var dataContext = Blaze.getData(eachView);
+            newDataContext = _.clone(dataContext) || {};
+            newDataContext[eachView.variableName] = item;
+          } else {
+            newDataContext = item;
           }
 
-          var newItemView = Blaze.With(item, eachView.contentFunc);
+          var newItemView = Blaze.With(newDataContext, eachView.contentFunc);
           eachView.numItems++;
 
           if (eachView.expandedValueDep) {