From f4a3059e56de5207f9c6812ca948f0fc407b7c61 Mon Sep 17 00:00:00 2001
From: Robert Jackson <robert.w.jackson@me.com>
Date: Fri, 4 Sep 2015 16:13:43 -0400
Subject: [PATCH] [BUGFIX beta] Remove double loop over attrs to create a
 component.

Previously, we would loop over `attrs` and create additional objects for
each entry then subsequently merge that "snapshot" back into a target
object TWICE for initial render.

This updates to loop once over the attrs and do all the work needed in
that one pass. It also avoids allocating two temporary objects and the
extra `Object.assign` to merge them back into the target.
---
 .../node-managers/component-node-manager.js   | 31 +++++++++----------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/packages/ember-htmlbars/lib/node-managers/component-node-manager.js b/packages/ember-htmlbars/lib/node-managers/component-node-manager.js
index 3aaafcb1a22..0be07a7211a 100644
--- a/packages/ember-htmlbars/lib/node-managers/component-node-manager.js
+++ b/packages/ember-htmlbars/lib/node-managers/component-node-manager.js
@@ -1,5 +1,4 @@
 import { assert, warn, runInDebug } from 'ember-metal/debug';
-import assign from 'ember-metal/assign';
 import buildComponentTemplate from 'ember-views/system/build-component-template';
 import getCellOrValue from 'ember-htmlbars/hooks/get-cell-or-value';
 import { get } from 'ember-metal/property_get';
@@ -255,17 +254,14 @@ ComponentNodeManager.prototype.destroy = function ComponentNodeManager_destroy()
   component.destroy();
 };
 
-export function createComponent(_component, isAngleBracket, _props, renderNode, env, attrs = {}) {
-  let props = assign({}, _props);
-
-  let snapshot = takeSnapshot(attrs);
-  props.attrs = snapshot;
-
+export function createComponent(_component, isAngleBracket, props, renderNode, env, attrs = {}) {
   if (!isAngleBracket) {
     assert('controller= is no longer supported', !('controller' in attrs));
 
-    mergeBindings(props, snapshot);
+    snapshotAndUpdateTarget(attrs, props);
   } else {
+    props.attrs = takeSnapshot(attrs);
+
     props._isAngleBracket = true;
   }
 
@@ -311,9 +307,13 @@ export function takeLegacySnapshot(attrs) {
   return hash;
 }
 
-function mergeBindings(target, attrs) {
-  for (var prop in attrs) {
-    if (!attrs.hasOwnProperty(prop)) { continue; }
+function snapshotAndUpdateTarget(rawAttrs, target) {
+  let attrs = {};
+
+  for (var prop in rawAttrs) {
+    let value = getCellOrValue(rawAttrs[prop]);
+    attrs[prop] = value;
+
     // when `attrs` is an actual value being set in the
     // attrs hash (`{{foo-bar attrs="blah"}}`) we cannot
     // set `"blah"` to the root of the target because
@@ -322,16 +322,15 @@ function mergeBindings(target, attrs) {
       warn(`Invoking a component with a hash attribute named \`attrs\` is not supported. Please refactor usage of ${target} to avoid passing \`attrs\` as a hash parameter.`, false, { id: 'ember-htmlbars.component-unsupported-attrs' });
       continue;
     }
-    let value = attrs[prop];
 
     if (value && value[MUTABLE_CELL]) {
-      target[prop] = value.value;
-    } else {
-      target[prop] = value;
+      value = value.value;
     }
+
+    target[prop] = value;
   }
 
-  return target;
+  return target.attrs = attrs;
 }
 
 function buildChildEnv(state, env) {