Remove superfluous error checking

IPython/html/static/widgets/js/manager.js

@@ -1,218 +1,215 b''
 // Copyright (c) IPython Development Team.
 // Distributed under the terms of the Modified BSD License.
 
 define([
     "underscore",
     "backbone",
     "jquery",
     "base/js/namespace"
 ], function (_, Backbone, $, IPython) {
     "use strict";
     //--------------------------------------------------------------------
     // WidgetManager class
     //--------------------------------------------------------------------
     var WidgetManager = function (comm_manager, notebook) {
         // Public constructor
         WidgetManager._managers.push(this);
 
         // Attach a comm manager to the 
         this.keyboard_manager = notebook.keyboard_manager;
         this.notebook = notebook;
         this.comm_manager = comm_manager;
         this._models = {}; /* Dictionary of model ids and model instances */
 
         // Register already-registered widget model types with the comm manager.
         var that = this;
         _.each(WidgetManager._model_types, function(model_type, model_name) {
             that.comm_manager.register_target(model_name, $.proxy(that._handle_comm_open, that));
         });
     };
 
     //--------------------------------------------------------------------
     // Class level
     //--------------------------------------------------------------------
     WidgetManager._model_types = {}; /* Dictionary of model type names (target_name) and model types. */
     WidgetManager._view_types = {}; /* Dictionary of view names and view types. */
     WidgetManager._managers = []; /* List of widget managers */
 
     WidgetManager.register_widget_model = function (model_name, model_type) {
         // Registers a widget model by name.
         WidgetManager._model_types[model_name] = model_type;
 
         // Register the widget with the comm manager.  Make sure to pass this object's context
         // in so `this` works in the call back.
         _.each(WidgetManager._managers, function(instance, i) {
             if (instance.comm_manager !== null) {
                 instance.comm_manager.register_target(model_name, $.proxy(instance._handle_comm_open, instance));
             }
         });
     };
 
     WidgetManager.register_widget_view = function (view_name, view_type) {
         // Registers a widget view by name.
         WidgetManager._view_types[view_name] = view_type;
     };
 
     //--------------------------------------------------------------------
     // Instance level
     //--------------------------------------------------------------------
     WidgetManager.prototype.display_view = function(msg, model) {
         // Displays a view for a particular model.
         var cell = this.get_msg_cell(msg.parent_header.msg_id);
         if (cell === null) {
             console.log("Could not determine where the display" + 
                 " message was from.  Widget will not be displayed");
         } else {
             var that = this;
             this.create_view(model, {cell: cell, callback: function(view) {
-                if (view === null) {
-                    console.error("View creation failed", model);
-                }
                 that._handle_display_view(view);
                 if (cell.widget_subarea) {
                     cell.widget_subarea.append(view.$el);
                 }
                 view.trigger('displayed');
             }});
         }
     };
 
     WidgetManager.prototype._handle_display_view = function (view) {
         // Have the IPython keyboard manager disable its event
         // handling so the widget can capture keyboard input.
         // Note, this is only done on the outer most widgets.
         if (this.keyboard_manager) {
             this.keyboard_manager.register_events(view.$el);
         
         if (view.additional_elements) {
             for (var i = 0; i < view.additional_elements.length; i++) {
                     this.keyboard_manager.register_events(view.additional_elements[i]);
             }
         } 
         }
     };
     
 
     WidgetManager.prototype.create_view = function(model, options) {
         // Creates a view for a particular model.
         
         var view_name = model.get('_view_name');
         var view_mod = model.get('_view_module');
         var errback = options.errback || function(err) {console.log(err);};
 
         var instantiate_view = function(ViewType) {
             if (ViewType) {
                 // If a view is passed into the method, use that view's cell as
                 // the cell for the view that is created.
                 options = options || {};
                 if (options.parent !== undefined) {
                     options.cell = options.parent.options.cell;
                 }
 
                 // Create and render the view...
                 var parameters = {model: model, options: options};
                 var view = new ViewType(parameters);
                 view.render();
                 model.on('destroy', view.remove, view);
                 options.callback(view);
             } else {
                 errback({unknown_view: true, view_name: view_name,
                          view_module: view_mod});
             }
         };
 
         if (view_mod) {
             require([view_mod], function(module) {
                 instantiate_view(module[view_name]);
             }, errback);
         } else {
             instantiate_view(WidgetManager._view_types[view_name]);
         }
     };
 
     WidgetManager.prototype.get_msg_cell = function (msg_id) {
         var cell = null;
         // First, check to see if the msg was triggered by cell execution.
         if (this.notebook) {
             cell = this.notebook.get_msg_cell(msg_id);
         }
         if (cell !== null) {
             return cell;
         }
         // Second, check to see if a get_cell callback was defined
         // for the message.  get_cell callbacks are registered for
         // widget messages, so this block is actually checking to see if the
         // message was triggered by a widget.
         var kernel = this.comm_manager.kernel;
         if (kernel) {
             var callbacks = kernel.get_callbacks_for_msg(msg_id);
             if (callbacks && callbacks.iopub &&
                 callbacks.iopub.get_cell !== undefined) {
                 return callbacks.iopub.get_cell();
             }
         }
         
         // Not triggered by a cell or widget (no get_cell callback 
         // exists).
         return null;
     };
 
     WidgetManager.prototype.callbacks = function (view) {
         // callback handlers specific a view
         var callbacks = {};
         if (view && view.options.cell) {
 
             // Try to get output handlers
             var cell = view.options.cell;
             var handle_output = null;
             var handle_clear_output = null;
             if (cell.output_area) {
                 handle_output = $.proxy(cell.output_area.handle_output, cell.output_area);
                 handle_clear_output = $.proxy(cell.output_area.handle_clear_output, cell.output_area);
             }
 
             // Create callback dict using what is known
             var that = this;
             callbacks = {
                 iopub : {
                     output : handle_output,
                     clear_output : handle_clear_output,
 
                     // Special function only registered by widget messages.
                     // Allows us to get the cell for a message so we know
                     // where to add widgets if the code requires it.
                     get_cell : function () {
                         return cell;
                     },
                 },
             };
         }
         return callbacks;
     };
 
     WidgetManager.prototype.get_model = function (model_id) {
         // Look-up a model instance by its id.
         var model = this._models[model_id];
         if (model !== undefined && model.id == model_id) {
             return model;
         }
         return null;
     };
 
     WidgetManager.prototype._handle_comm_open = function (comm, msg) {
         // Handle when a comm is opened.
         var that = this;
         var model_id = comm.comm_id;
         var widget_type_name = msg.content.target_name;
         var widget_model = new WidgetManager._model_types[widget_type_name](this, model_id, comm);
         widget_model.on('comm:close', function () {
           delete that._models[model_id];
         });
         this._models[model_id] = widget_model;
     };
 
     // Backwards compatability.
     IPython.WidgetManager = WidgetManager;
 
     return {'WidgetManager': WidgetManager};
 });