Backport PR jupyter-widgets#3370: Allow Output widget in html manager to render state updates

Author: jasongrout

examples/web3/jupyter-logo.svg

@@ -1,14 +1,19 @@
 [
-    "from ipywidgets import IntSlider, Text, VBox",
-    "from IPython.display import display",
-    "",
-    "s = IntSlider(max=200, value=100)",
-    "t = Text()",
-    "",
-    "def update_text(change=None):",
-    "    t.value = str(s.value ** 2)",
-    "",
-    "s.observe(update_text, names='value')",
-    "update_text()",
-    "display(VBox([s, t]))"
+  "from ipywidgets import IntSlider, Output, Text, VBox",
+  "from IPython.display import Image, display",
+  "",
+  "s = IntSlider(min=1, max=500, value=200, description='Width')",
+  "t = Text(description='Area', disabled=True)",
+  "o = Output()",
+  "display(VBox([s, t, o]))",
+  "",
+  "def update(change=None):",
+  "    width = s.value",
+  "    t.value = str(width ** 2)",
+  "    o.outputs = ()",
+  "    img = Image(url='jupyter-logo.svg', width=width)",
+  "    o.append_display_data(img)",
+  "",
+  "s.observe(update, names='value')",
+  "update()"
 ]

examples/web3/widget_code.json

@@ -14,29 +14,40 @@ import $ from 'jquery';
 import '../css/output.css';
 
 export class OutputModel extends outputBase.OutputModel {
-    defaults() {
-        return {
-            ...super.defaults(),
-            msg_id: ''
-        };
-    }
+  defaults(): Backbone.ObjectHash {
+    return {
+      ...super.defaults(),
+      msg_id: '',
+      outputs: [],
+    };
+  }
 
-    initialize(attributes: any, options: any) {
-        super.initialize(attributes, options);
-        this._outputs = new OutputAreaModel({
-            values: attributes.outputs,
-            // Widgets (including this output widget) are only rendered in
-            // trusted contexts
-            trusted: true,
-        });
-    }
+  initialize(attributes: any, options: any): void {
+    super.initialize(attributes, options);
+    this._outputs = new OutputAreaModel({ trusted: true });
+    this.listenTo(this, 'change:outputs', this.setOutputs);
+    this.setOutputs();
+  }
 
     get outputs() {
         return this._outputs;
     }
 
-    private _outputs: OutputAreaModel;
-    widget_manager: HTMLManager;
+  clear_output(wait = false): void {
+    this._outputs.clear(wait);
+  }
+
+  setOutputs(model?: any, value?: any, options?: any): void {
+    if (!(options && options.newMessage)) {
+      // fromJSON does not clear the existing output
+      this.clear_output();
+      // fromJSON does not copy the message, so we make a deep copy
+      this._outputs.fromJSON(JSON.parse(JSON.stringify(this.get('outputs'))));
+    }
+  }
+
+  private _outputs: OutputAreaModel;
+  widget_manager: HTMLManager;
 }
 
 export class OutputView extends outputBase.OutputView {

packages/html-manager/src/output.ts

@@ -21,6 +21,7 @@ const newWidget = async (modelState: any): Promise<HTMLElement> => {
         model_module_version: '*'
     };
     const model = await manager.new_model(modelCreate, modelState);
+<<<<<<< HEAD
     await manager.display_model(
         undefined, model, { el: widgetTag }
     );
@@ -205,4 +206,49 @@ describe('Output widget', function() {
         );
         expect(widgetTag.innerText).to.equal('something different');
     });
+=======
+    await manager.display_view(manager.create_view(model), widgetTag);
+    expect(widgetTag.innerText).to.equal('something different');
+  });
+
+  it('renders text output', async () => {
+    const manager = new HTMLManager();
+    const modelId = 'u-u-i-d';
+    const modelCreate: base.IModelOptions = {
+      model_name: 'OutputModel',
+      model_id: modelId,
+      model_module: '@jupyter-widgets/output',
+      model_module_version: '*',
+    };
+
+    const startingText = 'starting text';
+    const endingText = 'ending text';
+    const modelState = {
+      _view_module: '@jupyter-widgets/output',
+      outputs: [
+        {
+          output_type: 'stream',
+          name: 'stdout',
+          text: startingText,
+        },
+      ],
+    };
+
+    const widgetTag = document.createElement('div');
+    widgetTag.className = 'widget-subarea';
+    document.body.appendChild(widgetTag);
+    const model = await manager.new_model(modelCreate, modelState);
+    await manager.display_view(manager.create_view(model), widgetTag);
+    expect(widgetTag.innerText).to.equal(startingText);
+
+    model.set('outputs', [
+      {
+        output_type: 'stream',
+        name: 'stdout',
+        text: endingText,
+      },
+    ]);
+    expect(widgetTag.innerText).to.equal(endingText);
+  });
+>>>>>>> 20945261 (Merge pull request #3370 from MrBago/html-ow-update)
 });