Evaluate all script (grand)children of HTML output to render output o…

…f Bokeh and Plotly (#138)

* [WIP] Evaluate all script (grand)children of HTML output

* Improvements

* Remove TODO since it's probably resolved

* Update run.ts

* Update run.ts

* Also do this for plain HTML elements, not just for Python objects with _repr_html_

* Move line comment up and refer to it

* Fix typo

packages/starboard-python/src/global.ts

@@ -45,7 +45,7 @@ function drawCanvas(pixels: number[], width: number, height: number) {
   canvas.height = height;
   const ctx = canvas.getContext("2d");
   if (!ctx) {
-    console.warn("Failed to aquire canvas context");
+    console.warn("Failed to acquire canvas context");
     return;
   }
   ctx.putImageData(image, 0, 0);

packages/starboard-python/src/run.ts

@@ -53,6 +53,15 @@ export async function runStarboardPython(
 
       if (val instanceof HTMLElement) { // A plain HTML element
         htmlOutput.appendChild(val);
+        // Just putting HTML with script tags on the DOM will not get them evaluated
+        // Using this hack we execute them anyway
+        val.querySelectorAll('script[type|="text/javascript"]').forEach(
+              function(e) {
+                if (e.textContent !== null) {
+                  eval(e.textContent);
+                }
+              }
+            )
       } else if (typeof val === "object" && val.name === "PythonError" && val.__error_address) { // A python error
         error = val;
         outputElement.addEntry({
@@ -69,6 +78,14 @@ export async function runStarboardPython(
             div.className = "rendered_html cell-output-html";
             div.appendChild(new DOMParser().parseFromString(result, "text/html").body.firstChild as any);
             htmlOutput.appendChild(div);
+            // Evaluate all script tags manually, see previous comment
+            div.querySelectorAll('script[type|="text/javascript"]').forEach(
+              function(e) {
+                if (e.textContent !== null) {
+                  eval(e.textContent);
+                }
+              }
+            )
             hadHTMLOutput = true;
           }
         } else if (val._repr_latex_ !== undefined) { // It has a LateX representation (e.g. Sympy output)