JS -- Add listener for sandbox events only if there are some actions

* When no actions then set it to null instead of empty object
* Even if a field has no actions, it needs to listen to events from the sandbox in order to be updated if an action changes something in it.

src/core/document.js

@@ -1020,6 +1020,21 @@ class PDFDocument {
     );
   }
 
+  get hasJSActions() {
+    return shadow(
+      this,
+      "hasJSActions",
+      this.fieldObjects.then(fieldObjects => {
+        return (
+          fieldObjects !== null &&
+          Object.values(fieldObjects).some(fieldObject =>
+            fieldObject.some(object => object.actions !== null)
+          )
+        );
+      })
+    );
+  }
+
   get calculationOrderIds() {
     const acroForm = this.catalog.acroForm;
     if (!acroForm || !acroForm.has("CO")) {

src/core/worker.js

@@ -525,6 +525,10 @@ class WorkerMessageHandler {
       return pdfManager.ensureDoc("fieldObjects");
     });
 
+    handler.on("HasJSActions", function (data) {
+      return pdfManager.ensureDoc("hasJSActions");
+    });
+
     handler.on("GetCalculationOrderIds", function (data) {
       return pdfManager.ensureDoc("calculationOrderIds");
     });

src/display/annotation_layer.js

@@ -43,6 +43,8 @@ import { AnnotationStorage } from "./annotation_storage.js";
  *   for annotation icons. Include trailing slash.
  * @property {boolean} renderInteractiveForms
  * @property {Object} svgFactory
+ * @property {boolean} [enableScripting]
+ * @property {boolean} [hasJSActions]
  */
 
 class AnnotationElementFactory {
@@ -142,6 +144,8 @@ class AnnotationElement {
     this.renderInteractiveForms = parameters.renderInteractiveForms;
     this.svgFactory = parameters.svgFactory;
     this.annotationStorage = parameters.annotationStorage;
+    this.enableScripting = parameters.enableScripting;
+    this.hasJSActions = parameters.hasJSActions;
 
     if (isRenderable) {
       this.container = this._createContainer(ignoreBorder);
@@ -507,7 +511,7 @@ class TextWidgetAnnotationElement extends WidgetAnnotationElement {
         event.target.setSelectionRange(0, 0);
       });
 
-      if (this.data.actions) {
+      if (this.enableScripting && this.hasJSActions) {
         element.addEventListener("updateFromSandbox", function (event) {
           const data = event.detail;
           if ("value" in data) {
@@ -517,21 +521,23 @@ class TextWidgetAnnotationElement extends WidgetAnnotationElement {
           }
         });
 
-        for (const eventType of Object.keys(this.data.actions)) {
-          switch (eventType) {
-            case "Format":
-              element.addEventListener("blur", function (event) {
-                window.dispatchEvent(
-                  new CustomEvent("dispatchEventInSandbox", {
-                    detail: {
-                      id,
-                      name: "Format",
-                      value: event.target.value,
-                    },
-                  })
-                );
-              });
-              break;
+        if (this.data.actions !== null) {
+          for (const eventType of Object.keys(this.data.actions)) {
+            switch (eventType) {
+              case "Format":
+                element.addEventListener("blur", function (event) {
+                  window.dispatchEvent(
+                    new CustomEvent("dispatchEventInSandbox", {
+                      detail: {
+                        id,
+                        name: "Format",
+                        value: event.target.value,
+                      },
+                    })
+                  );
+                });
+                break;
+            }
           }
         }
       }
@@ -1562,6 +1568,9 @@ class FileAttachmentAnnotationElement extends AnnotationElement {
  * @property {string} [imageResourcesPath] - Path for image resources, mainly
  *   for annotation icons. Include trailing slash.
  * @property {boolean} renderInteractiveForms
+ * @property {boolean} [enableScripting] - Enable embedded script execution.
+ * @property {boolean} [hasJSActions] - Some fields have JS actions.
+ *   The default value is `false`.
  */
 
 class AnnotationLayer {
@@ -1608,6 +1617,8 @@ class AnnotationLayer {
         svgFactory: new DOMSVGFactory(),
         annotationStorage:
           parameters.annotationStorage || new AnnotationStorage(),
+        enableScripting: parameters.enableScripting,
+        hasJSActions: parameters.hasJSActions,
       });
       if (element.isRenderable) {
         const rendered = element.render();

src/display/api.js

@@ -903,6 +903,14 @@ class PDFDocumentProxy {
     return this._transport.getFieldObjects();
   }
 
+  /**
+   * @returns {Promise<boolean>} A promise that is resolved with `true`
+   * if some /AcroForm fields have JavaScript actions.
+   */
+  hasJSActions() {
+    return this._transport.hasJSActions();
+  }
+
   /**
    * @returns {Promise<Array<string> | null>} A promise that is resolved with an
    *   {Array<string>} containing IDs of annotations that have a calculation
@@ -2568,6 +2576,10 @@ class WorkerTransport {
     return this.messageHandler.sendWithPromise("GetFieldObjects", null);
   }
 
+  hasJSActions() {
+    return this.messageHandler.sendWithPromise("HasJSActions", null);
+  }
+
   getCalculationOrderIds() {
     return this.messageHandler.sendWithPromise("GetCalculationOrderIds", null);
   }

src/scripting_api/field.js

@@ -73,12 +73,14 @@ class Field extends PDFObject {
     // Private
     this._actions = Object.create(null);
     const doc = (this._document = data.doc);
-    for (const [eventType, actions] of Object.entries(data.actions)) {
-      // This code is running in a sandbox so it's safe to use Function
-      this._actions[eventType] = actions.map(action =>
-        // eslint-disable-next-line no-new-func
-        Function("event", `with (this) {${action}}`).bind(doc)
-      );
+    if (data.actions !== null) {
+      for (const [eventType, actions] of Object.entries(data.actions)) {
+        // This code is running in a sandbox so it's safe to use Function
+        this._actions[eventType] = actions.map(action =>
+          // eslint-disable-next-line no-new-func
+          Function("event", `with (this) {${action}}`).bind(doc)
+        );
+      }
     }
   }