Replace a bunch of Array.prototype.forEach() cases with for...of loops instead

Using `for...of` is a modern and generally much nicer pattern, since it gets rid of unnecessary callback-functions. (In a couple of spots, a "regular" `for` loop had to be used.)

src/core/evaluator.js

@@ -1394,9 +1394,9 @@ class PartialEvaluator {
       ) {
         const groupIds = [];
         if (Array.isArray(optionalContentGroups)) {
-          optionalContent.get("OCGs").forEach(ocg => {
+          for (const ocg of optionalContentGroups) {
             groupIds.push(ocg.toString());
-          });
+          }
         } else {
           // Dictionary, just use the obj id.
           groupIds.push(optionalContentGroups.objId);

src/core/function.js

@@ -1337,13 +1337,14 @@ var PostScriptCompiler = (function PostScriptCompilerClosure() {
       }
 
       var result = [];
-      instructions.forEach(function (instruction) {
+      for (const instruction of instructions) {
-        var statementBuilder = new ExpressionBuilderVisitor();
+        const statementBuilder = new ExpressionBuilderVisitor();
         instruction.visit(statementBuilder);
         result.push(statementBuilder.toString());
-      });
+      }
-      stack.forEach(function (expr, i) {
+      for (let i = 0, ii = stack.length; i < ii; i++) {
-        var statementBuilder = new ExpressionBuilderVisitor();
+        const expr = stack[i],
+          statementBuilder = new ExpressionBuilderVisitor();
         expr.visit(statementBuilder);
         var min = range[i * 2],
           max = range[i * 2 + 1];
@@ -1359,7 +1360,7 @@ var PostScriptCompiler = (function PostScriptCompilerClosure() {
         out.unshift("dest[destOffset + ", i, "] = ");
         out.push(";");
         result.push(out.join(""));
-      });
+      }
       return result.join("\n");
     }
   }

src/core/worker.js

@@ -785,10 +785,10 @@ class WorkerMessageHandler {
         cancelXHRs(new AbortException("Worker was terminated."));
       }
 
-      WorkerTasks.forEach(function (task) {
+      for (const task of WorkerTasks) {
         waitOn.push(task.finished);
         task.terminate();
-      });
+      }
 
       return Promise.all(waitOn).then(function () {
         // Notice that even if we destroying handler, resolved response promise

src/core/worker_stream.js

@@ -43,10 +43,9 @@ class PDFWorkerStream {
     if (this._fullRequestReader) {
       this._fullRequestReader.cancel(reason);
     }
-    const readers = this._rangeRequestReaders.slice(0);
+    for (const reader of this._rangeRequestReaders.slice(0)) {
-    readers.forEach(function (reader) {
       reader.cancel(reason);
-    });
+    }
   }
 }
 

src/display/annotation_layer.js

@@ -343,9 +343,9 @@ class AnnotationElement {
       assert(this.quadrilaterals, "Missing quadrilaterals during rendering");
     }
 
-    this.quadrilaterals.forEach(quadrilateral => {
+    for (const quadrilateral of this.quadrilaterals) {
       quadrilateral.className = className;
-    });
+    }
     return this.quadrilaterals;
   }
 
@@ -1445,11 +1445,11 @@ class PopupElement {
     }
 
     // Attach the event listeners to the trigger element.
-    this.trigger.forEach(element => {
+    for (const element of this.trigger) {
       element.addEventListener("click", this._toggle.bind(this));
       element.addEventListener("mouseover", this._show.bind(this, false));
       element.addEventListener("mouseout", this._hide.bind(this, false));
-    });
+    }
     popup.addEventListener("click", this._hide.bind(this, true));
 
     wrapper.appendChild(popup);
@@ -2104,9 +2104,9 @@ class AnnotationLayer {
         `[data-annotation-id="${data.id}"]`
       );
       if (elements) {
-        elements.forEach(element => {
+        for (const element of elements) {
           element.style.transform = transform;
-        });
+        }
       }
     }
     parameters.div.hidden = false;

src/display/api.js

@@ -2289,11 +2289,11 @@ class WorkerTransport {
     const waitOn = [];
     // We need to wait for all renderings to be completed, e.g.
     // timeout/rAF can take a long time.
-    this.pageCache.forEach(function (page) {
+    for (const page of this.pageCache) {
       if (page) {
         waitOn.push(page._destroy());
       }
-    });
+    }
     this.pageCache.length = 0;
     this.pagePromises.length = 0;
     // Allow `AnnotationStorage`-related clean-up when destroying the document.

src/display/fetch_stream.js

@@ -91,10 +91,9 @@ class PDFFetchStream {
     if (this._fullRequestReader) {
       this._fullRequestReader.cancel(reason);
     }
-    const readers = this._rangeRequestReaders.slice(0);
+    for (const reader of this._rangeRequestReaders.slice(0)) {
-    readers.forEach(function (reader) {
       reader.cancel(reason);
-    });
+    }
   }
 }
 

src/display/font_loader.js

@@ -61,9 +61,9 @@ class BaseFontLoader {
   }
 
   clear() {
-    this.nativeFontFaces.forEach(nativeFontFace => {
+    for (const nativeFontFace of this.nativeFontFaces) {
       this._document.fonts.delete(nativeFontFace);
-    });
+    }
     this.nativeFontFaces.length = 0;
 
     if (this.styleElement) {

src/display/network.js

@@ -259,10 +259,9 @@ class PDFNetworkStream {
     if (this._fullRequestReader) {
       this._fullRequestReader.cancel(reason);
     }
-    const readers = this._rangeRequestReaders.slice(0);
+    for (const reader of this._rangeRequestReaders.slice(0)) {
-    readers.forEach(function (reader) {
       reader.cancel(reason);
-    });
+    }
   }
 }
 
@@ -348,9 +347,9 @@ class PDFNetworkStreamFullRequestReader {
     if (this._cachedChunks.length > 0) {
       return;
     }
-    this._requests.forEach(function (requestCapability) {
+    for (const requestCapability of this._requests) {
       requestCapability.resolve({ value: undefined, done: true });
-    });
+    }
     this._requests = [];
   }
 
@@ -359,9 +358,9 @@ class PDFNetworkStreamFullRequestReader {
     const exception = createResponseStatusError(status, url);
     this._storedError = exception;
     this._headersReceivedCapability.reject(exception);
-    this._requests.forEach(function (requestCapability) {
+    for (const requestCapability of this._requests) {
       requestCapability.reject(exception);
-    });
+    }
     this._requests = [];
     this._cachedChunks = [];
   }
@@ -414,9 +413,9 @@ class PDFNetworkStreamFullRequestReader {
   cancel(reason) {
     this._done = true;
     this._headersReceivedCapability.reject(reason);
-    this._requests.forEach(function (requestCapability) {
+    for (const requestCapability of this._requests) {
       requestCapability.resolve({ value: undefined, done: true });
-    });
+    }
     this._requests = [];
     if (this._manager.isPendingRequest(this._fullRequestId)) {
       this._manager.abortRequest(this._fullRequestId);
@@ -457,9 +456,9 @@ class PDFNetworkStreamRangeRequestReader {
       this._queuedChunk = chunk;
     }
     this._done = true;
-    this._requests.forEach(function (requestCapability) {
+    for (const requestCapability of this._requests) {
       requestCapability.resolve({ value: undefined, done: true });
-    });
+    }
     this._requests = [];
     this._close();
   }
@@ -492,9 +491,9 @@ class PDFNetworkStreamRangeRequestReader {
 
   cancel(reason) {
     this._done = true;
-    this._requests.forEach(function (requestCapability) {
+    for (const requestCapability of this._requests) {
       requestCapability.resolve({ value: undefined, done: true });
-    });
+    }
     this._requests = [];
     if (this._manager.isPendingRequest(this._requestId)) {
       this._manager.abortRequest(this._requestId);

src/display/node_stream.js

@@ -98,11 +98,9 @@ class PDFNodeStream {
     if (this._fullRequestReader) {
       this._fullRequestReader.cancel(reason);
     }
-
+    for (const reader of this._rangeRequestReaders.slice(0)) {
-    const readers = this._rangeRequestReaders.slice(0);
-    readers.forEach(function (reader) {
       reader.cancel(reason);
-    });
+    }
   }
 }
 

src/display/svg.js

@@ -1370,9 +1370,9 @@ if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
         // The previous clipping group content can go out of order -- resetting
         // cached clipGroups.
         current.clipGroup = null;
-        this.extraStack.forEach(function (prev) {
+        for (const prev of this.extraStack) {
           prev.clipGroup = null;
-        });
+        }
         // Intersect with the previous clipping path.
         clipPath.setAttributeNS(null, "clip-path", current.activeClipUrl);
       }

src/display/text_layer.js

@@ -312,8 +312,8 @@ const renderTextLayer = (function renderTextLayerClosure() {
       // Finding intersections with expanded box.
       const points = [[0, 0], [0, b.size[1]], [b.size[0], 0], b.size];
       const ts = new Float64Array(64);
-      points.forEach(function (p, j) {
+      for (let j = 0, jj = points.length; j < jj; j++) {
-        const t = Util.applyTransform(p, m);
+        const t = Util.applyTransform(points[j], m);
         ts[j + 0] = c && (e.left - t[0]) / c;
         ts[j + 4] = s && (e.top - t[1]) / s;
         ts[j + 8] = c && (e.right - t[0]) / c;
@@ -333,7 +333,7 @@ const renderTextLayer = (function renderTextLayerClosure() {
         ts[j + 52] = c && (e.top - t[1]) / -c;
         ts[j + 56] = s && (e.right - t[0]) / s;
         ts[j + 60] = c && (e.bottom - t[1]) / -c;
-      });
+      }
       // Not based on math, but to simplify calculations, using cos and sin
       // absolute values to not exceed the box (it can but insignificantly).
       const boxScale = 1 + Math.min(Math.abs(c), Math.abs(s));
@@ -358,8 +358,9 @@ const renderTextLayer = (function renderTextLayerClosure() {
       };
     });
     expandBoundsLTR(width, bounds);
+
     const expanded = new Array(boxes.length);
-    bounds.forEach(function (b) {
+    for (const b of bounds) {
       const i = b.index;
       expanded[i] = {
         left: b.x1New,
@@ -367,7 +368,7 @@ const renderTextLayer = (function renderTextLayerClosure() {
         right: b.x2New,
         bottom: 0,
       };
-    });
+    }
 
     // Rotating on 90 degrees and extending extended boxes. Reusing the bounds
     // array and objects.
@@ -384,11 +385,11 @@ const renderTextLayer = (function renderTextLayerClosure() {
     });
     expandBoundsLTR(height, bounds);
 
-    bounds.forEach(function (b) {
+    for (const b of bounds) {
       const i = b.index;
       expanded[i].top = b.x1New;
       expanded[i].bottom = b.x2New;
-    });
+    }
     return expanded;
   }
 
@@ -416,7 +417,7 @@ const renderTextLayer = (function renderTextLayerClosure() {
       },
     ];
 
-    bounds.forEach(function (boundary) {
+    for (const boundary of bounds) {
       // Searching for the affected part of horizon.
       // TODO red-black tree or simple binary search
       let i = 0;
@@ -555,15 +556,15 @@ const renderTextLayer = (function renderTextLayerClosure() {
         horizon,
         [i, j - i + 1].concat(changedHorizon)
       );
-    });
+    }
 
     // Set new x2 for all unset boundaries.
-    horizon.forEach(function (horizonPart) {
+    for (const horizonPart of horizon) {
       const affectedBoundary = horizonPart.boundary;
       if (affectedBoundary.x2New === undefined) {
         affectedBoundary.x2New = Math.max(width, affectedBoundary.x2);
       }
-    });
+    }
   }
 
   /**

src/display/transport_stream.js

@@ -147,10 +147,9 @@ class PDFDataTransportStream {
     if (this._fullRequestReader) {
       this._fullRequestReader.cancel(reason);
     }
-    const readers = this._rangeReaders.slice(0);
+    for (const reader of this._rangeReaders.slice(0)) {
-    readers.forEach(function (rangeReader) {
+      reader.cancel(reason);
-      rangeReader.cancel(reason);
+    }
-    });
     this._pdfDataRangeTransport.abort();
   }
 }
@@ -228,9 +227,9 @@ class PDFDataTransportStreamReader {
 
   cancel(reason) {
     this._done = true;
-    this._requests.forEach(function (requestCapability) {
+    for (const requestCapability of this._requests) {
       requestCapability.resolve({ value: undefined, done: true });
-    });
+    }
     this._requests = [];
   }
 
@@ -264,9 +263,9 @@ class PDFDataTransportStreamRangeReader {
     } else {
       const requestsCapability = this._requests.shift();
       requestsCapability.resolve({ value: chunk, done: false });
-      this._requests.forEach(function (requestCapability) {
+      for (const requestCapability of this._requests) {
         requestCapability.resolve({ value: undefined, done: true });
-      });
+      }
       this._requests = [];
     }
     this._done = true;
@@ -293,9 +292,9 @@ class PDFDataTransportStreamRangeReader {
 
   cancel(reason) {
     this._done = true;
-    this._requests.forEach(function (requestCapability) {
+    for (const requestCapability of this._requests) {
       requestCapability.resolve({ value: undefined, done: true });
-    });
+    }
     this._requests = [];
     this._stream._removeRangeReader(this);
   }

web/ui_utils.js

@@ -775,22 +775,22 @@ class EventBus {
     let externalListeners;
     // Making copy of the listeners array in case if it will be modified
     // during dispatch.
-    eventListeners.slice(0).forEach(({ listener, external, once }) => {
+    for (const { listener, external, once } of eventListeners.slice(0)) {
       if (once) {
         this._off(eventName, listener);
       }
       if (external) {
         (externalListeners ||= []).push(listener);
-        return;
+        continue;
       }
       listener.apply(null, args);
-    });
+    }
     // Dispatch any "external" listeners *after* the internal ones, to give the
     // viewer components time to handle events and update their state first.
     if (externalListeners) {
-      externalListeners.forEach(listener => {
+      for (const listener of externalListeners) {
         listener.apply(null, args);
-      });
+      }
       externalListeners = null;
     }
     if (