diff --git a/src/core/worker.js b/src/core/worker.js
index 700493103..0f6276fb2 100644
--- a/src/core/worker.js
+++ b/src/core/worker.js
@@ -391,8 +391,8 @@ class WorkerMessageHandler {
         .then(pdfManagerReady, onFailure);
     }
 
-    handler.on("GetPage", function (data) {
-      return pdfManager.getPage(data.pageIndex).then(function (page) {
+    handler.on("GetPage", function ({ pageIndex }) {
+      return pdfManager.getPage(pageIndex).then(function (page) {
         return Promise.all([
           pdfManager.ensure(page, "rotate"),
           pdfManager.ensure(page, "ref"),
@@ -410,73 +410,65 @@ class WorkerMessageHandler {
       });
     });
 
-    handler.on("GetPageIndex", function (data) {
-      const pageRef = Ref.get(data.num, data.gen);
-      return pdfManager.ensureCatalog("getPageIndex", [pageRef]);
+    handler.on("GetPageIndex", function ({ num, gen }) {
+      return pdfManager.ensureCatalog("getPageIndex", [Ref.get(num, gen)]);
     });
 
-    handler.on("GetDestinations", function (data) {
+    handler.on("GetDestinations", function () {
       return pdfManager.ensureCatalog("destinations");
     });
 
-    handler.on("GetDestination", function (data) {
-      return pdfManager.ensureCatalog("getDestination", [data.id]);
+    handler.on("GetDestination", function ({ id }) {
+      return pdfManager.ensureCatalog("getDestination", [id]);
     });
 
-    handler.on("GetPageLabels", function (data) {
+    handler.on("GetPageLabels", function () {
       return pdfManager.ensureCatalog("pageLabels");
     });
 
-    handler.on("GetPageLayout", function (data) {
+    handler.on("GetPageLayout", function () {
       return pdfManager.ensureCatalog("pageLayout");
     });
 
-    handler.on("GetPageMode", function (data) {
+    handler.on("GetPageMode", function () {
       return pdfManager.ensureCatalog("pageMode");
     });
 
-    handler.on("GetViewerPreferences", function (data) {
+    handler.on("GetViewerPreferences", function () {
       return pdfManager.ensureCatalog("viewerPreferences");
     });
 
-    handler.on("GetOpenAction", function (data) {
+    handler.on("GetOpenAction", function () {
       return pdfManager.ensureCatalog("openAction");
     });
 
-    handler.on("GetAttachments", function (data) {
+    handler.on("GetAttachments", function () {
       return pdfManager.ensureCatalog("attachments");
     });
 
-    handler.on(
-      "GetAttachmentContent",
-      /**
-       * @param {string} id
-       *   Unique attachment identifier (required).
-       */
-      async function (id) {
-        let passwordEx;
+    handler.on("GetAttachmentContent", async function (id) {
+      let passwordEx;
 
-        // Loop to prompt again after an incorrect password.
-        while (true) {
-          const password = passwordEx ? await getPassword(passwordEx) : null;
+      // Loop to prompt again after an incorrect password.
+      while (true) {
+        const password = passwordEx ? await getPassword(passwordEx) : null;
 
-          try {
-            if (password) {
-              pdfManager.updatePassword(password);
-            }
-            return await pdfManager.ensureCatalog("attachmentContent", [id]);
-          } catch (ex) {
-            if (ex instanceof PasswordException) {
-              passwordEx = ex;
-              continue;
-            }
-            throw ex;
+        try {
+          if (password) {
+            pdfManager.updatePassword(password);
           }
+          return await pdfManager.ensureCatalog("attachmentContent", [id]);
+        } catch (ex) {
+          if (ex instanceof PasswordException) {
+            passwordEx = ex;
+            continue;
+          }
+          throw ex;
         }
       }
-    );
+    });
 
-    handler.on("GetDocJSActions", function (data) {
+    handler.on("GetDocJSActions", function () {
       return pdfManager.ensureCatalog("jsActions");
     });
 
@@ -534,19 +526,19 @@ class WorkerMessageHandler {
       }
     );
 
-    handler.on("GetOutline", function (data) {
+    handler.on("GetOutline", function () {
       return pdfManager.ensureCatalog("documentOutline");
     });
 
-    handler.on("GetOptionalContentConfig", function (data) {
+    handler.on("GetOptionalContentConfig", function () {
       return pdfManager.ensureCatalog("optionalContentConfig");
     });
 
-    handler.on("GetPermissions", function (data) {
+    handler.on("GetPermissions", function () {
       return pdfManager.ensureCatalog("permissions");
     });
 
-    handler.on("GetMetadata", function (data) {
+    handler.on("GetMetadata", function () {
       return Promise.all([
         pdfManager.ensureDoc("documentInfo"),
         pdfManager.ensureCatalog("metadata"),
@@ -554,11 +546,11 @@ class WorkerMessageHandler {
       ]);
     });
 
-    handler.on("GetMarkInfo", function (data) {
+    handler.on("GetMarkInfo", function () {
       return pdfManager.ensureCatalog("markInfo");
     });
 
-    handler.on("GetData", function (data) {
+    handler.on("GetData", function () {
       return pdfManager.requestLoadedStream().then(stream => stream.bytes);
     });
 
@@ -573,13 +565,13 @@ class WorkerMessageHandler {
       });
     });
 
-    handler.on("GetFieldObjects", function (data) {
+    handler.on("GetFieldObjects", function () {
       return pdfManager
         .ensureDoc("fieldObjects")
         .then(fieldObjects => fieldObjects?.allFields || null);
     });
 
-    handler.on("GetSignatures", function (data) {
+    handler.on("GetSignatures", function () {
       return pdfManager.ensureDoc("signatures");
     });
 
@@ -587,11 +579,11 @@ class WorkerMessageHandler {
       return pdfManager.ensureDoc("getSignatureData", [id]);
     });
 
-    handler.on("HasJSActions", function (data) {
+    handler.on("HasJSActions", function () {
       return pdfManager.ensureDoc("hasJSActions");
     });
 
-    handler.on("GetCalculationOrderIds", function (data) {
+    handler.on("GetCalculationOrderIds", function () {
       return pdfManager.ensureDoc("calculationOrderIds");
     });
 
@@ -893,96 +885,104 @@ class WorkerMessageHandler {
       }
     );
 
-    handler.on("GetOperatorList", function (data, sink) {
-      const { pageId, pageIndex } = data;
-      pdfManager.getPage(pageId).then(function (page) {
-        const task = new WorkerTask(`GetOperatorList: page ${pageIndex}`);
-        startWorkerTask(task);
+    handler.on(
+      "GetOperatorList",
+      function (
+        { pageId, pageIndex, intent, cacheKey, annotationStorage, modifiedIds },
+        sink
+      ) {
+        pdfManager.getPage(pageId).then(function (page) {
+          const task = new WorkerTask(`GetOperatorList: page ${pageIndex}`);
+          startWorkerTask(task);
 
-        // NOTE: Keep this condition in sync with the `info` helper function.
-        const start = verbosity >= VerbosityLevel.INFOS ? Date.now() : 0;
+          // NOTE: Keep this condition in sync with the `info` helper function.
+          const start = verbosity >= VerbosityLevel.INFOS ? Date.now() : 0;
 
-        // Pre compile the pdf page and fetch the fonts/images.
-        page
-          .getOperatorList({
-            handler,
-            sink,
-            task,
-            intent: data.intent,
-            cacheKey: data.cacheKey,
-            annotationStorage: data.annotationStorage,
-            modifiedIds: data.modifiedIds,
-            pageIndex,
-          })
-          .then(
-            opListInfo => {
-              if (start) {
-                info(
-                  `${task.name}; time=${Date.now() - start}ms, len=${opListInfo.length}`
-                );
+          // Pre compile the pdf page and fetch the fonts/images.
+          page
+            .getOperatorList({
+              handler,
+              sink,
+              task,
+              intent,
+              cacheKey,
+              annotationStorage,
+              modifiedIds,
+              pageIndex,
+            })
+            .then(
+              opListInfo => {
+                if (start) {
+                  info(
+                    `${task.name}; time=${Date.now() - start}ms, len=${opListInfo.length}`
+                  );
+                }
+                sink.close();
+              },
+              reason => {
+                if (task.terminated) {
+                  return; // ignoring errors from the terminated thread
+                }
+                sink.error(reason);
               }
-              sink.close();
-            },
-            reason => {
-              if (task.terminated) {
-                return; // ignoring errors from the terminated thread
+            )
+            .finally(() => {
+              finishWorkerTask(task);
+            });
+        });
+      }
+    );
+
+    handler.on(
+      "GetTextContent",
+      function (
+        { pageId, pageIndex, includeMarkedContent, disableNormalization },
+        sink
+      ) {
+        pdfManager.getPage(pageId).then(function (page) {
+          const task = new WorkerTask("GetTextContent: page " + pageIndex);
+          startWorkerTask(task);
+
+          // NOTE: Keep this condition in sync with the `info` helper function.
+          const start = verbosity >= VerbosityLevel.INFOS ? Date.now() : 0;
+
+          page
+            .extractTextContent({
+              handler,
+              task,
+              sink,
+              includeMarkedContent,
+              disableNormalization,
+            })
+            .then(
+              () => {
+                if (start) {
+                  info(`${task.name}; time=${Date.now() - start}ms`);
+                }
+                sink.close();
+              },
+              reason => {
+                if (task.terminated) {
+                  return; // ignoring errors from the terminated thread
+                }
+                sink.error(reason);
               }
-              sink.error(reason);
-            }
-          )
-          .finally(() => {
-            finishWorkerTask(task);
-          });
-      });
-    });
+            )
+            .finally(() => {
+              finishWorkerTask(task);
+            });
+        });
+      }
+    );
 
-    handler.on("GetTextContent", function (data, sink) {
-      const { pageId, pageIndex, includeMarkedContent, disableNormalization } =
-        data;
-
-      pdfManager.getPage(pageId).then(function (page) {
-        const task = new WorkerTask("GetTextContent: page " + pageIndex);
-        startWorkerTask(task);
-
-        // NOTE: Keep this condition in sync with the `info` helper function.
-        const start = verbosity >= VerbosityLevel.INFOS ? Date.now() : 0;
-
-        page
-          .extractTextContent({
-            handler,
-            task,
-            sink,
-            includeMarkedContent,
-            disableNormalization,
-          })
-          .then(
-            () => {
-              if (start) {
-                info(`${task.name}; time=${Date.now() - start}ms`);
-              }
-              sink.close();
-            },
-            reason => {
-              if (task.terminated) {
-                return; // ignoring errors from the terminated thread
-              }
-              sink.error(reason);
-            }
-          )
-          .finally(() => {
-            finishWorkerTask(task);
-          });
-      });
-    });
-
-    handler.on("GetStructTree", function (data) {
+    handler.on("GetStructTree", function ({ pageIndex }) {
       return pdfManager
-        .getPage(data.pageIndex)
+        .getPage(pageIndex)
         .then(page => pdfManager.ensure(page, "getStructTree"));
     });
 
-    handler.on("FontFallback", function (data) {
-      return pdfManager.fontFallback(data.id, handler);
+    handler.on("FontFallback", function ({ id }) {
+      return pdfManager.fontFallback(id, handler);
     });
 
     if (
@@ -1005,11 +1005,11 @@ class WorkerMessageHandler {
       });
     }
 
-    handler.on("Cleanup", function (data) {
+    handler.on("Cleanup", function () {
       return pdfManager.cleanup(/* manuallyTriggered = */ true);
     });
 
-    handler.on("Terminate", async function (data) {
+    handler.on("Terminate", async function () {
       terminated = true;
 
       const waitOn = [];
@@ -1037,21 +1037,21 @@ class WorkerMessageHandler {
       handler = null;
     });
 
-    handler.on("Ready", function (data) {
+    handler.on("Ready", function () {
       setupDoc(docParams);
       docParams = null; // we don't need docParams anymore -- saving memory.
     });
 
     if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
-      handler.on("GetXFADatasets", function (data) {
+      handler.on("GetXFADatasets", function () {
         return pdfManager.ensureDoc("xfaDatasets");
       });
-      handler.on("GetStartXRefPos", function (data) {
+      handler.on("GetStartXRefPos", function () {
         return pdfManager.ensureDoc("startXRef");
       });
-      handler.on("GetAnnotArray", function (data) {
+      handler.on("GetAnnotArray", function ({ pageIndex }) {
         return pdfManager
-          .getPage(data.pageIndex)
+          .getPage(pageIndex)
           .then(page => page.annotations.map(a => a.toString()));
       });
       handler.on("GetWorkerCoverage", function () {