Use shorter arrow functions where possible

For arrow functions that are both simple and short, we can avoid using explicit `return` to shorten them even further without hurting readability.

For the `gulp mozcentral` build-target this reduces the overall size of the output by just under 1 kilo-byte (which isn't a lot but still can't hurt).

src/core/annotation.js

@@ -4824,9 +4824,7 @@ class StampAnnotation extends MarkupAnnotation {
 
     const jpegBufferPromise = canvas
       .convertToBlob({ type: "image/jpeg", quality: 1 })
-      .then(blob => {
-        return blob.arrayBuffer();
-      });
+      .then(blob => blob.arrayBuffer());
 
     const xobjectName = Name.get("XObject");
     const imageName = Name.get("Image");

src/core/cmap.js

@@ -691,9 +691,9 @@ async function createBuiltInCMap(name, fetchBuiltInCMap) {
   const cMap = new CMap(true);
 
   if (compressionType === CMapCompressionType.BINARY) {
-    return new BinaryCMapReader().process(cMapData, cMap, useCMap => {
-      return extendCMap(cMap, fetchBuiltInCMap, useCMap);
-    });
+    return new BinaryCMapReader().process(cMapData, cMap, useCMap =>
+      extendCMap(cMap, fetchBuiltInCMap, useCMap)
+    );
   }
   if (compressionType === CMapCompressionType.NONE) {
     const lexer = new Lexer(new Stream(cMapData));

src/core/fonts.js

@@ -2093,9 +2093,7 @@ class Font {
           endOffset: 0,
         });
       }
-      locaEntries.sort((a, b) => {
-        return a.offset - b.offset;
-      });
+      locaEntries.sort((a, b) => a.offset - b.offset);
       // Now the offsets are sorted, calculate the end offset of each glyph.
       // The last loca entry's endOffset is not calculated since it's the end
       // of the data and will be stored on the previous entry's endOffset.
@@ -2103,9 +2101,7 @@ class Font {
         locaEntries[i].endOffset = locaEntries[i + 1].offset;
       }
       // Re-sort so glyphs aren't out of order.
-      locaEntries.sort((a, b) => {
-        return a.index - b.index;
-      });
+      locaEntries.sort((a, b) => a.index - b.index);
       // Calculate the endOffset of the "first" glyph correctly when there are
       // *multiple* empty ones at the start of the data (fixes issue14618.pdf).
       for (i = 0; i < numGlyphs; i++) {

src/core/writer.js

@@ -344,10 +344,9 @@ async function incrementalUpdate({
 
   // Add a ref for the new xref and sort them
   newRefs.push({ ref: refForXrefTable, data: "" });
-  newRefs = newRefs.sort((a, b) => {
-    // compare the refs
-    return a.ref.num - b.ref.num;
-  });
+  newRefs = newRefs.sort(
+    (a, b) => /* compare the refs */ a.ref.num - b.ref.num
+  );
 
   const xrefTableData = [[0, 1, 0xffff]];
   const indexes = [0, 1];

src/display/api.js

@@ -771,19 +771,13 @@ class PDFDocumentProxy {
     if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
       // For testing purposes.
       Object.defineProperty(this, "getXFADatasets", {
-        value: () => {
-          return this._transport.getXFADatasets();
-        },
+        value: () => this._transport.getXFADatasets(),
       });
       Object.defineProperty(this, "getXRefPrevValue", {
-        value: () => {
-          return this._transport.getXRefPrevValue();
-        },
+        value: () => this._transport.getXRefPrevValue(),
       });
       Object.defineProperty(this, "getAnnotArray", {
-        value: pageIndex => {
-          return this._transport.getAnnotArray(pageIndex);
-        },
+        value: pageIndex => this._transport.getAnnotArray(pageIndex),
       });
     }
   }
@@ -1628,9 +1622,7 @@ class PDFPageProxy {
     if (this._transport._htmlForXfa) {
       // TODO: We need to revisit this once the XFA foreground patch lands and
       // only do this for non-foreground XFA.
-      return this.getXfa().then(xfa => {
-        return XfaText.textContent(xfa);
-      });
+      return this.getXfa().then(xfa => XfaText.textContent(xfa));
     }
     const readableStream = this.streamTextContent(params);
 
@@ -2358,21 +2350,16 @@ class WorkerTransport {
     if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
       // For testing purposes.
       Object.defineProperty(this, "getXFADatasets", {
-        value: () => {
-          return this.messageHandler.sendWithPromise("GetXFADatasets", null);
-        },
+        value: () =>
+          this.messageHandler.sendWithPromise("GetXFADatasets", null),
       });
       Object.defineProperty(this, "getXRefPrevValue", {
-        value: () => {
-          return this.messageHandler.sendWithPromise("GetXRefPrevValue", null);
-        },
+        value: () =>
+          this.messageHandler.sendWithPromise("GetXRefPrevValue", null),
       });
       Object.defineProperty(this, "getAnnotArray", {
-        value: pageIndex => {
-          return this.messageHandler.sendWithPromise("GetAnnotArray", {
-            pageIndex,
-          });
-        },
+        value: pageIndex =>
+          this.messageHandler.sendWithPromise("GetAnnotArray", { pageIndex }),
       });
     }
   }
@@ -2737,9 +2724,7 @@ class WorkerTransport {
 
           this.fontLoader
             .bind(font)
-            .catch(reason => {
-              return messageHandler.sendWithPromise("FontFallback", { id });
-            })
+            .catch(() => messageHandler.sendWithPromise("FontFallback", { id }))
             .finally(() => {
               if (!params.fontExtraProperties && font.data) {
                 // Immediately release the `font.data` property once the font
@@ -3013,9 +2998,7 @@ class WorkerTransport {
   getOptionalContentConfig() {
     return this.messageHandler
       .sendWithPromise("GetOptionalContentConfig", null)
-      .then(results => {
-        return new OptionalContentConfig(results);
-      });
+      .then(results => new OptionalContentConfig(results));
   }
 
   getPermissions() {
@@ -3192,9 +3175,7 @@ class RenderTask {
     if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
       // For testing purposes.
       Object.defineProperty(this, "getOperatorList", {
-        value: () => {
-          return this.#internalRenderTask.operatorList;
-        },
+        value: () => this.#internalRenderTask.operatorList,
       });
     }
   }

src/display/display_utils.js

@@ -483,9 +483,9 @@ class DOMStandardFontDataFactory extends BaseStandardFontDataFactory {
    * @ignore
    */
   _fetchData(url) {
-    return fetchData(url, /* type = */ "arraybuffer").then(data => {
-      return new Uint8Array(data);
-    });
+    return fetchData(url, /* type = */ "arraybuffer").then(
+      data => new Uint8Array(data)
+    );
   }
 }
 

src/display/fetch_stream.js

@@ -147,9 +147,8 @@ class PDFFetchStreamReader {
         this._reader = response.body.getReader();
         this._headersCapability.resolve();
 
-        const getResponseHeader = name => {
-          return response.headers.get(name);
-        };
+        const getResponseHeader = name => response.headers.get(name);
+
         const { allowRangeRequests, suggestedLength } =
           validateRangeRequestCapabilities({
             getResponseHeader,

src/display/network.js

@@ -279,9 +279,8 @@ class PDFNetworkStreamFullRequestReader {
     const fullRequestXhrId = this._fullRequestId;
     const fullRequestXhr = this._manager.getRequestXhr(fullRequestXhrId);
 
-    const getResponseHeader = name => {
-      return fullRequestXhr.getResponseHeader(name);
-    };
+    const getResponseHeader = name => fullRequestXhr.getResponseHeader(name);
+
     const { allowRangeRequests, suggestedLength } =
       validateRangeRequestCapabilities({
         getResponseHeader,

src/display/node_stream.js

@@ -326,11 +326,11 @@ class PDFNodeStreamFullReader extends BaseFullReader {
       this._headersCapability.resolve();
       this._setReadableStream(response);
 
-      const getResponseHeader = name => {
-        // Make sure that headers name are in lower case, as mentioned
-        // here: https://nodejs.org/api/http.html#http_message_headers.
-        return this._readableStream.headers[name.toLowerCase()];
-      };
+      // Make sure that headers name are in lower case, as mentioned
+      // here: https://nodejs.org/api/http.html#http_message_headers.
+      const getResponseHeader = name =>
+        this._readableStream.headers[name.toLowerCase()];
+
       const { allowRangeRequests, suggestedLength } =
         validateRangeRequestCapabilities({
           getResponseHeader,

src/pdf.sandbox.js

@@ -141,9 +141,7 @@ class Sandbox {
 }
 
 function QuickJSSandbox() {
-  return ModuleLoader().then(module => {
-    return new Sandbox(window, module);
-  });
+  return ModuleLoader().then(module => new Sandbox(window, module));
 }
 
 export { QuickJSSandbox };

src/scripting_api/util.js

@@ -212,66 +212,26 @@ class Util extends PDFObject {
     }
 
     const handlers = {
-      mmmm: data => {
-        return this._months[data.month];
-      },
-      mmm: data => {
-        return this._months[data.month].substring(0, 3);
-      },
-      mm: data => {
-        return (data.month + 1).toString().padStart(2, "0");
-      },
-      m: data => {
-        return (data.month + 1).toString();
-      },
-      dddd: data => {
-        return this._days[data.dayOfWeek];
-      },
-      ddd: data => {
-        return this._days[data.dayOfWeek].substring(0, 3);
-      },
-      dd: data => {
-        return data.day.toString().padStart(2, "0");
-      },
-      d: data => {
-        return data.day.toString();
-      },
-      yyyy: data => {
-        return data.year.toString();
-      },
-      yy: data => {
-        return (data.year % 100).toString().padStart(2, "0");
-      },
-      HH: data => {
-        return data.hours.toString().padStart(2, "0");
-      },
-      H: data => {
-        return data.hours.toString();
-      },
-      hh: data => {
-        return (1 + ((data.hours + 11) % 12)).toString().padStart(2, "0");
-      },
-      h: data => {
-        return (1 + ((data.hours + 11) % 12)).toString();
-      },
-      MM: data => {
-        return data.minutes.toString().padStart(2, "0");
-      },
-      M: data => {
-        return data.minutes.toString();
-      },
-      ss: data => {
-        return data.seconds.toString().padStart(2, "0");
-      },
-      s: data => {
-        return data.seconds.toString();
-      },
-      tt: data => {
-        return data.hours < 12 ? "am" : "pm";
-      },
-      t: data => {
-        return data.hours < 12 ? "a" : "p";
-      },
+      mmmm: data => this._months[data.month],
+      mmm: data => this._months[data.month].substring(0, 3),
+      mm: data => (data.month + 1).toString().padStart(2, "0"),
+      m: data => (data.month + 1).toString(),
+      dddd: data => this._days[data.dayOfWeek],
+      ddd: data => this._days[data.dayOfWeek].substring(0, 3),
+      dd: data => data.day.toString().padStart(2, "0"),
+      d: data => data.day.toString(),
+      yyyy: data => data.year.toString(),
+      yy: data => (data.year % 100).toString().padStart(2, "0"),
+      HH: data => data.hours.toString().padStart(2, "0"),
+      H: data => data.hours.toString(),
+      hh: data => (1 + ((data.hours + 11) % 12)).toString().padStart(2, "0"),
+      h: data => (1 + ((data.hours + 11) % 12)).toString(),
+      MM: data => data.minutes.toString().padStart(2, "0"),
+      M: data => data.minutes.toString(),
+      ss: data => data.seconds.toString().padStart(2, "0"),
+      s: data => data.seconds.toString(),
+      tt: data => (data.hours < 12 ? "am" : "pm"),
+      t: data => (data.hours < 12 ? "a" : "p"),
     };
 
     const data = {