From 848742ff1f25a093d5d6fcbe9ab386873c8f1ea6 2014-10-16 19:20:35
From: Matthias Bussonnier <bussonniermatthias@gmail.com>
Date: 2014-10-16 19:20:35
Subject: [PATCH] Use low overhead object heritence in Js (Object.create vs new)

the use of

    XX.prototype = new YY();

Does trigger the constructor of YY without the nead for it. `Object.create`
does go around this limitation and target browser that are relatively Old.

Cf https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/create

for more info

It might help to get rid of some logic in constructors that check wether some
options are passed in, that were causing errors on noteboko load.  Typically
`if(element){ }` on Abstract  `Cell` constructor.

---

diff --git a/IPython/html/static/notebook/js/codecell.js b/IPython/html/static/notebook/js/codecell.js
index 37df9c3..c6d19c8 100644
--- a/IPython/html/static/notebook/js/codecell.js
+++ b/IPython/html/static/notebook/js/codecell.js
@@ -115,7 +115,7 @@ define([
 
     CodeCell.msg_cells = {};
 
-    CodeCell.prototype = new Cell();
+    CodeCell.prototype = Object.create(Cell.prototype);
 
     /**
      * @method auto_highlight
diff --git a/IPython/html/static/notebook/js/maintoolbar.js b/IPython/html/static/notebook/js/maintoolbar.js
index 7b56a86..6bb0f1b 100644
--- a/IPython/html/static/notebook/js/maintoolbar.js
+++ b/IPython/html/static/notebook/js/maintoolbar.js
@@ -27,7 +27,7 @@ define([
         this.bind_events();
     };
 
-    MainToolBar.prototype = new toolbar.ToolBar();
+    MainToolBar.prototype = Object.create(toolbar.ToolBar.prototype);
 
     MainToolBar.prototype.construct = function () {
         var that = this;
diff --git a/IPython/html/static/notebook/js/scrollmanager.js b/IPython/html/static/notebook/js/scrollmanager.js
index a93dcbc..45a3f83 100644
--- a/IPython/html/static/notebook/js/scrollmanager.js
+++ b/IPython/html/static/notebook/js/scrollmanager.js
@@ -68,7 +68,7 @@ define(['jquery'], function($){
         // Public constructor.
         ScrollManager.apply(this, [notebook, options]);
     };
-    TargetScrollManager.prototype = new ScrollManager();
+    TargetScrollManager.prototype = Object.create(ScrollManager.prototype);
 
     TargetScrollManager.prototype.is_target = function (index) {
         // Check if a cell should be a scroll stop.
@@ -114,7 +114,7 @@ define(['jquery'], function($){
         // Public constructor.
         TargetScrollManager.apply(this, [notebook, options]);
     };
-    SlideScrollManager.prototype = new TargetScrollManager();
+    SlideScrollManager.prototype = Object.create(TargetScrollManager.prototype);
 
     SlideScrollManager.prototype.is_target = function (index) {
         var cell = this.notebook.get_cell(index);
@@ -131,7 +131,7 @@ define(['jquery'], function($){
         options = options || {};
         this._level = options.heading_level || 1;
     };
-    HeadingScrollManager.prototype = new ScrollManager();
+    HeadingScrollManager.prototype = Object.create(ScrollManager.prototype)
 
     HeadingScrollManager.prototype.scroll = function (delta) {
         // Scroll the document.
diff --git a/IPython/html/static/notebook/js/textcell.js b/IPython/html/static/notebook/js/textcell.js
index f4668c9..89f112f 100644
--- a/IPython/html/static/notebook/js/textcell.js
+++ b/IPython/html/static/notebook/js/textcell.js
@@ -55,7 +55,7 @@ define([
         this.rendered = false;
     };
 
-    TextCell.prototype = new Cell();
+    TextCell.prototype = Object.create(Cell.prototype);
 
     TextCell.options_default = {
         cm_config : {
@@ -220,7 +220,7 @@ define([
         placeholder: "Type *Markdown* and LaTeX: $\\alpha^2$"
     };
 
-    MarkdownCell.prototype = new TextCell();
+    MarkdownCell.prototype = Object.create(TextCell.prototype);
 
     /**
      * @method render
@@ -270,7 +270,7 @@ define([
             "When passing through nbconvert, a Raw Cell's content is added to the output unmodified."
     };
 
-    RawCell.prototype = new TextCell();
+    RawCell.prototype = Object.create(TextCell.prototype);
 
     /** @method bind_events **/
     RawCell.prototype.bind_events = function () {
@@ -330,7 +330,7 @@ define([
         placeholder: "Type Heading Here"
     };
 
-    HeadingCell.prototype = new TextCell();
+    HeadingCell.prototype = Object.create(TextCell.prototype);
 
     /** @method fromJSON */
     HeadingCell.prototype.fromJSON = function (data) {