From 70918d33eefd9c636c37e81856c1770c0b6db31c Mon Sep 17 00:00:00 2001
From: Jason Grout <jgrout6@bloomberg.net>
Date: Wed, 26 Apr 2017 17:15:50 -0400
Subject: [PATCH] Make the widget manager totally responsible for loading a
 class.

---
 .../examples/web3/src/manager.ts              | 12 ++++
 .../examples/web5/src/manager.ts              | 12 ++++
 jupyter-js-widgets/src-embed/embed-manager.ts | 29 +++++----
 jupyter-js-widgets/src-embed/embed-webpack.ts | 55 ++++++++---------
 jupyter-js-widgets/src/manager-base.ts        | 53 +++++++---------
 jupyter-js-widgets/src/utils.ts               | 60 -------------------
 jupyter-js-widgets/test/src/dummy-manager.ts  | 20 +++++--
 jupyterlab_widgets/src/index.ts               |  4 +-
 widgetsnbextension/src/manager.js             | 12 +++-
 9 files changed, 118 insertions(+), 139 deletions(-)

diff --git a/jupyter-js-widgets/examples/web3/src/manager.ts b/jupyter-js-widgets/examples/web3/src/manager.ts
index 381f5e1c23..eb2cbac235 100644
--- a/jupyter-js-widgets/examples/web3/src/manager.ts
+++ b/jupyter-js-widgets/examples/web3/src/manager.ts
@@ -28,6 +28,18 @@ class WidgetManager extends widgets.ManagerBase<HTMLElement> {
         });
     }
 
+    protected loadClass(className: string, moduleName: string, moduleVersion: string): Promise<any> {
+        if (moduleName === 'jupyter-js-widgets') {
+            if (widgets[className]) {
+                return Promise.resolve(widgets[className]);
+            } else {
+                return Promise.reject(`Cannot find class ${className}`)
+            }
+        } else {
+            return Promise.reject(`Cannot find module ${moduleName}`);
+        }
+    }
+
     _create_comm(targetName, id, metadata) {
         return this.commManager.new_comm(targetName, metadata, id);
     }
diff --git a/jupyter-js-widgets/examples/web5/src/manager.ts b/jupyter-js-widgets/examples/web5/src/manager.ts
index ad16b327d0..13f99d264c 100644
--- a/jupyter-js-widgets/examples/web5/src/manager.ts
+++ b/jupyter-js-widgets/examples/web5/src/manager.ts
@@ -27,6 +27,18 @@ class WidgetManager extends widgets.ManagerBase<HTMLElement> {
         });
     }
 
+    protected loadClass(className: string, moduleName: string, moduleVersion: string): Promise<any> {
+        if (moduleName === 'jupyter-js-widgets') {
+            if (widgets[className]) {
+                return Promise.resolve(widgets[className]);
+            } else {
+                return Promise.reject(`Cannot find class ${className}`)
+            }
+        } else {
+            return Promise.reject(`Cannot find module ${moduleName}`);
+        }
+    }
+
     _create_comm(targetName, id, metadata) {
         return this.commManager.new_comm(targetName, metadata, id);
     }
diff --git a/jupyter-js-widgets/src-embed/embed-manager.ts b/jupyter-js-widgets/src-embed/embed-manager.ts
index 386c9f056c..bbe7a4c52c 100644
--- a/jupyter-js-widgets/src-embed/embed-manager.ts
+++ b/jupyter-js-widgets/src-embed/embed-manager.ts
@@ -7,6 +7,8 @@ import {
 
 import * as PhosphorWidget from '@phosphor/widgets';
 
+import * as widgets from '../../jupyter-js-widgets/lib/index';
+
 export
 class EmbedManager extends ManagerBase<HTMLElement> {
 
@@ -43,18 +45,25 @@ class EmbedManager extends ManagerBase<HTMLElement> {
     };
 
     /**
-     * Takes a requirejs success handler and returns a requirejs error handler
-     * that attempts loading the module from unpkg.
+     * Load a class and return a promise to the loaded object.
      */
-    require_error(success_callback, failure_callback, version : string) {
-        return function(err) : any {
-            var failedId = err.requireModules && err.requireModules[0];
-            if (failedId) {
-                // TODO: Get typing to work for requirejs
-                (window as any).require(['https://unpkg.com/' + failedId + '@' + version + '/dist/index.js'], success_callback);
+    protected loadClass(className: string, moduleName: string, moduleVersion: string) {
+        return new Promise(function(resolve, reject) {
+            if (moduleName === 'jupyter-js-widgets') {
+                // Shortcut resolving the standard widgets so we don't load two
+                // copies on the page. If we ever separate the embed manager
+                // from the main widget package, we should get rid of this special
+                // case.
+                resolve(widgets);
+            } else {
+                (window as any).require([`https://unpkg.com/${moduleName}@${moduleVersion}/dist/index.js`], resolve, reject);
+            }
+        }).then(function(module) {
+            if (module[className]) {
+                return module[className];
             } else {
-                failure_callback(err);
+                return Promise.reject(`Class ${className} not found in module ${moduleName}@${moduleVersion}`);
             }
-        };
+        });
     }
 };
diff --git a/jupyter-js-widgets/src-embed/embed-webpack.ts b/jupyter-js-widgets/src-embed/embed-webpack.ts
index 2351920cb3..06dce09df8 100644
--- a/jupyter-js-widgets/src-embed/embed-webpack.ts
+++ b/jupyter-js-widgets/src-embed/embed-webpack.ts
@@ -6,7 +6,7 @@
 
 // Element.prototype.matches polyfill
 if (Element && !Element.prototype.matches) {
-    var proto = Element.prototype as any;
+    let proto = Element.prototype as any;
     proto.matches = proto.matchesSelector ||
     proto.mozMatchesSelector || proto.msMatchesSelector ||
     proto.oMatchesSelector || proto.webkitMatchesSelector;
@@ -31,22 +31,19 @@ import * as _ from 'underscore';
 // All it does is inserting a <script> tag for requirejs in the case it is not
 // available and call `renderInlineWidgets`
 function loadInlineWidgets(event) {
-    // If requirejs is not on the page on page load, load it from cdn.
-    if (!(window as any).requirejs) {
-        var scriptjs = require('scriptjs') as any;
-        scriptjs('https://unpkg.com/requirejs/require.js', function() {
-            // Define jupyter-js-widget requirejs module
-            //
-            // (This is needed for custom widget model to be able to AMD require jupyter-js-widgets.)
-            (window as any).define('jupyter-js-widgets', function() {
-                return widgets;
+    let loadRequire = new Promise(function(resolve, reject) {
+        if ((window as any).requirejs) {
+            resolve();
+        } else {
+            // If requirejs is not on the page on page load, load it from cdn.
+            let scriptjs = require('scriptjs') as any;
+            scriptjs('https://unpkg.com/requirejs/require.js', function() {
+                resolve();
             });
-            // Render inline widgets
-            renderInlineWidgets(event);
-        });
-    } else {
+        }
+    });
+    loadRequire.then(function() {
         // Define jupyter-js-widget requirejs module
-        //
         // (This is needed for custom widget model to be able to AMD require jupyter-js-widgets.)
         if (!(window as any).requirejs.defined('jupyter-js-widgets')) {
             (window as any).define('jupyter-js-widgets', function () {
@@ -55,7 +52,7 @@ function loadInlineWidgets(event) {
         }
         // Render inline widgets
         renderInlineWidgets(event);
-    }
+    });
 }
 
 // `renderInlineWidget` will call `renderManager(element, tag)` on each <script>
@@ -63,9 +60,9 @@ function loadInlineWidgets(event) {
 //     "application/vnd.jupyter.widget-state+json"
 // contained in `event.element`.
 export function renderInlineWidgets(event) {
-    var element = event.target || document;
-    var tags = element.querySelectorAll('script[type="application/vnd.jupyter.widget-state+json"]');
-    for (var i=0; i!=tags.length; ++i) {
+    let element = event.target || document;
+    let tags = element.querySelectorAll('script[type="application/vnd.jupyter.widget-state+json"]');
+    for (let i=0; i!=tags.length; ++i) {
         renderManager(element, tags[i]);
     }
 }
@@ -76,28 +73,28 @@ export function renderInlineWidgets(event) {
 // Then it performs a look up of all script tags under the specified DOM
 // element with the mime type
 //     "application/vnd.jupyter.widget-view+json".
-// For each oone of these <script> tag, if the contained json specifies a model id
+// For each one of these <script> tags, if the contained json specifies a model id
 // known to the aforementioned manager, it is replaced with a view of the model.
 //
 // Besides, if the view script tag has an <img> sibling DOM node with class `jupyter-widget`,
 // the <img> tag is deleted.
 function renderManager(element, tag) {
-    var widgetStateObject = JSON.parse(tag.innerHTML);
-    var ajv = new Ajv(); // options can be passed, e.g. {allErrors: true}
-    var model_validate = ajv.compile(widget_state_schema);
-    var valid = model_validate(widgetStateObject);
+    let widgetStateObject = JSON.parse(tag.innerHTML);
+    let ajv = new Ajv(); // options can be passed, e.g. {allErrors: true}
+    let model_validate = ajv.compile(widget_state_schema);
+    let valid = model_validate(widgetStateObject);
     if (!valid) {
         console.log(model_validate.errors);
     }
-    var manager = new embed.EmbedManager();
+    let manager = new embed.EmbedManager();
     manager.set_state(widgetStateObject, {}).then(function(models) {
-        var tags = element.querySelectorAll('script[type="application/vnd.jupyter.widget-view+json"]');
-        for (var i=0; i!=tags.length; ++i) {
+        let tags = element.querySelectorAll('script[type="application/vnd.jupyter.widget-view+json"]');
+        for (let i=0; i!=tags.length; ++i) {
             // TODO: validate view schema
             let viewtag = tags[i];
             let widgetViewObject = JSON.parse(viewtag.innerHTML);
-            var view_validate = ajv.compile(widget_view_schema);
-            var valid = view_validate(widgetViewObject);
+            let view_validate = ajv.compile(widget_view_schema);
+            let valid = view_validate(widgetViewObject);
             if (!valid) {
                 console.log(view_validate.errors);
             }
diff --git a/jupyter-js-widgets/src/manager-base.ts b/jupyter-js-widgets/src/manager-base.ts
index c05595815c..8787fde7d1 100644
--- a/jupyter-js-widgets/src/manager-base.ts
+++ b/jupyter-js-widgets/src/manager-base.ts
@@ -144,11 +144,9 @@ abstract class ManagerBase<T> {
     create_view(model, options) {
         model.state_change = model.state_change.then(() => {
 
-            return this.loadClass(
-                model.get('_view_name'),
+            return this.loadClass(model.get('_view_name'),
                 model.get('_view_module'),
-                model.get('_view_module_version'),
-                this.require_error
+                model.get('_view_module_version')
             ).then((ViewType) => {
                 var view = new ViewType({
                     model: model,
@@ -206,7 +204,7 @@ abstract class ManagerBase<T> {
 
     /**
      * Create a comm and new widget model.
-     * @param  options - same options as new_model but, comm is not
+     * @param  options - same options as new_model but comm is not
      *                          required and additional options are available.
      * @param  serialized_state - serialized model attributes.
      */
@@ -327,11 +325,11 @@ abstract class ManagerBase<T> {
             return widget_model;
         };
 
-        var model_promise = this.loadClass(options.model_name,
-                                           options.model_module,
-                                           options.model_module_version,
-                                           that.require_error)
-        .then(function(ModelType) {
+        let model_promise = this.loadClass(
+            options.model_name,
+            options.model_module,
+            options.model_module_version
+        ).then(function(ModelType) {
             try {
                 return ModelType._deserialize_state(serialized_state || {}, that)
                 .then(function(attributes) {
@@ -450,22 +448,19 @@ abstract class ManagerBase<T> {
                     });
                 }
 
+                let modelCreate: ModelOptions = {
+                    model_id: model_id,
+                    model_name: model.model_name,
+                    model_module: model.model_module,
+                    model_module_version: model.model_module_version
+                };
                 if (live_comms.hasOwnProperty(model_id)) {  // live comm
-                    return this._create_comm(this.comm_target_name, model_id).then(new_comm => {
-                        return this.new_model({
-                            comm: new_comm,
-                            model_name: models[model_id].model_name,
-                            model_module: models[model_id].model_module,
-                            model_module_version: models[model_id].model_module_version
-                        });
+                    return this._create_comm(this.comm_target_name, model_id).then(comm => {
+                        modelCreate.comm = comm;
+                        return this.new_model(modelCreate);
                     });
-                } else {                                    // dead comm
-                    return this.new_model({
-                        model_id: model_id,
-                        model_name: models[model_id].model_name,
-                        model_module: models[model_id].model_module,
-                        model_module_version: models[model_id].model_module_version
-                    }, modelState);
+                } else {
+                    return this.new_model(modelCreate, modelState);
                 }
             }));
         });
@@ -476,13 +471,9 @@ abstract class ManagerBase<T> {
     /**
      * Load a class and return a promise to the loaded object.
      */
-    protected loadClass(className, moduleName, moduleVersion, error) {
-        return utils.loadClass(className, moduleName, moduleVersion, null, error);
-    }
-
-    abstract _create_comm(comm_target_name, model_id, data?): Promise<any>;
-
-    abstract _get_comm_info();
+    protected abstract loadClass(className: string, moduleName: string, moduleVersion: string): Promise<any>;
+    protected abstract _create_comm(comm_target_name, model_id, data?): Promise<any>;
+    protected abstract _get_comm_info();
 
     /**
      * Dictionary of model ids and model instance promises
diff --git a/jupyter-js-widgets/src/utils.ts b/jupyter-js-widgets/src/utils.ts
index a42fdee45c..b0730d9948 100644
--- a/jupyter-js-widgets/src/utils.ts
+++ b/jupyter-js-widgets/src/utils.ts
@@ -45,66 +45,6 @@ class WrappedError extends Error {
     error_stack: any[];
 }
 
-/**
- * Tries to load a class
- *
- * Tries to load a class from a module using require.js, if a module
- * is specified, otherwise tries to load a class from the global
- * registry, if the global registry is provided.
- *
- * The optional require_error argument is a function that takes the success
- * handler and returns a requirejs error handler, which may call the success
- * handler with a fallback module.
- *
- */
-
-export
-function loadClass(class_name, module_name, module_version, registry, require_error): Promise<any> {
-    return new Promise(function(resolve, reject) {
-
-        // Try loading the view module using require.js
-        if (module_name) {
-            // If the module is jupyter-js-widgets, we can just self import.
-            var modulePromise;
-            var requirejsDefined = typeof window !== 'undefined' && (window as any).requirejs;
-            if (requirejsDefined) {
-                if (module_name !== 'jupyter-js-widgets' || (window as any).requirejs.defined('jupyter-js-widgets')) {
-                    modulePromise = new Promise(function(innerResolve, innerReject) {
-                        var success_callback = function(module) {
-                            innerResolve(module);
-                        };
-                        var failure_callback = require_error ? require_error(success_callback, reject, module_version) : reject;
-                        (window as any).require([module_name], success_callback, failure_callback);
-                    });
-                } else if (module_name === 'jupyter-js-widgets') {
-                    modulePromise = Promise.resolve(require('../'));
-                }
-            } else if (module_name === 'jupyter-js-widgets') {
-                modulePromise = Promise.resolve(require('../'));
-            } else {
-                // FUTURE: Investigate dynamic loading methods other than require.js.
-                throw new Error(['In order to use third party widgets, you ',
-                    'must have require.js loaded on the page.'].join(''));
-            }
-
-            modulePromise.then(function(module) {
-                if (module[class_name] === undefined) {
-                    reject(new Error('Class ' + class_name + ' not found in module ' + module_name));
-                } else {
-                    resolve(module[class_name]);
-                }
-            });
-        } else {
-            if (registry && registry[class_name]) {
-                resolve(registry[class_name]);
-            } else {
-                reject(new Error('Class ' + class_name + ' not found in registry '));
-            }
-        }
-    });
-}
-
-
 /**
  * Resolve a promiseful dictionary.
  * Returns a single Promise.
diff --git a/jupyter-js-widgets/test/src/dummy-manager.ts b/jupyter-js-widgets/test/src/dummy-manager.ts
index da75925a06..0f73455c9c 100644
--- a/jupyter-js-widgets/test/src/dummy-manager.ts
+++ b/jupyter-js-widgets/test/src/dummy-manager.ts
@@ -3,9 +3,7 @@
 
 import expect = require('expect.js');
 
-import {
-    ManagerBase
-} from '../../lib';
+import * as widgets from '../../lib';
 import * as services from '@jupyterlab/services';
 import * as Backbone from 'backbone';
 
@@ -17,7 +15,7 @@ class MockComm {
 }
 
 export
-class DummyManager extends ManagerBase<HTMLElement> {
+class DummyManager extends widgets.ManagerBase<HTMLElement> {
     constructor() {
         super();
         this.el = window.document.createElement('div');
@@ -30,7 +28,19 @@ class DummyManager extends ManagerBase<HTMLElement> {
             return view.el;
         });
     }
-    
+
+    protected loadClass(className: string, moduleName: string, moduleVersion: string): Promise<any> {
+        if (moduleName === 'jupyter-js-widgets') {
+            if (widgets[className]) {
+                return Promise.resolve(widgets[className]);
+            } else {
+                return Promise.reject(`Cannot find class ${className}`)
+            }
+        } else {
+            return Promise.reject(`Cannot find module ${moduleName}`);
+        }
+    }
+
     _get_comm_info() {
         return Promise.resolve({});
     }
diff --git a/jupyterlab_widgets/src/index.ts b/jupyterlab_widgets/src/index.ts
index 6cd1933e53..f5b8aff806 100644
--- a/jupyterlab_widgets/src/index.ts
+++ b/jupyterlab_widgets/src/index.ts
@@ -179,10 +179,10 @@ class WidgetManager extends ManagerBase<Widget> implements IDisposable {
   /**
    * Load a class and return a promise to the loaded object.
    */
-  protected loadClass(className: string, moduleName: string, moduleVersion: string, error: any): any {
+  protected loadClass(className: string, moduleName: string, moduleVersion: string): any {
     let mod: any = this._registry.get(moduleName, moduleVersion);
     if (!mod) {
-    return Promise.reject(`Module ${moduleName}, semver range ${moduleVersion} is not registered as a widget module`);
+      return Promise.reject(`Module ${moduleName}, semver range ${moduleVersion} is not registered as a widget module`);
     }
     let cls: any = mod[className];
     if (!cls) {
diff --git a/widgetsnbextension/src/manager.js b/widgetsnbextension/src/manager.js
index ce394bc662..b456478e18 100644
--- a/widgetsnbextension/src/manager.js
+++ b/widgetsnbextension/src/manager.js
@@ -140,7 +140,7 @@ WidgetManager.set_state_callbacks(function() {
     }
 });
 
-WidgetManager.prototype.loadClass = function(className, moduleName, moduleVersion, error) {
+WidgetManager.prototype.loadClass = function(className, moduleName, moduleVersion) {
     if (moduleName === "jupyter-js-widgets") {
         if (className === "OutputModel" || className === "OutputView") {
             return Promise.resolve(output[className]);
@@ -148,7 +148,15 @@ WidgetManager.prototype.loadClass = function(className, moduleName, moduleVersio
             return Promise.resolve(widgets[className]);
         }
     } else {
-        return Object.getPrototypeOf(WidgetManager.prototype).loadClass.apply(this, arguments);
+        return new Promise(function(resolve, reject) {
+            window.require([moduleName], resolve, reject);
+        }).then(function(mod) {
+            if (mod[className]) {
+                return mod[className];
+            } else {
+                return Promise.reject('Class ' + className + ' not found in module ' + moduleName);
+            }
+        });
     }
 }