Add a makeSet helper, to reduce function creation

This replaces inline `() => new Set()` statements, and also makes some `getOrInsertComputed` calls slightly shorter.

src/core/glyf.js

@@ -13,6 +13,8 @@
  * limitations under the License.
  */
 
+import { makeSet } from "../shared/util.js";
+
 const ON_CURVE_POINT = 1 << 0;
 const X_SHORT_VECTOR = 1 << 1;
 const Y_SHORT_VECTOR = 1 << 2;
@@ -756,13 +758,7 @@ function pruneCompositeGlyphCycles(glyfTable, locaEntries, numGlyphs) {
         stack.push({ node: next, idx: 0 });
         continue;
       }
-
-      let removeSet = backEdges.get(top.node);
-      if (!removeSet) {
-        removeSet = new Set();
-        backEdges.set(top.node, removeSet);
-      }
-      removeSet.add(compIdx);
+      backEdges.getOrInsertComputed(top.node, makeSet).add(compIdx);
     }
   }
 

src/core/image_utils.js

@@ -13,7 +13,7 @@
  * limitations under the License.
  */
 
-import { assert, unreachable, warn } from "../shared/util.js";
+import { assert, makeSet, unreachable, warn } from "../shared/util.js";
 import { RefSet, RefSetCache } from "./primitives.js";
 
 class BaseLocalCache {
@@ -228,7 +228,7 @@ class GlobalImageCache {
   }
 
   shouldCache(ref, pageIndex) {
-    const pageIndexSet = this._refCache.getOrPutComputed(ref, () => new Set());
+    const pageIndexSet = this._refCache.getOrPutComputed(ref, makeSet);
     pageIndexSet.add(pageIndex);
 
     if (pageIndexSet.size < GlobalImageCache.NUM_PAGES_THRESHOLD) {

src/pdf.js

@@ -36,6 +36,7 @@ import {
   makeArr,
   makeMap,
   makeObj,
+  makeSet,
   normalizeUnicode,
   OPS,
   PasswordException,
@@ -131,6 +132,7 @@ globalThis.pdfjsLib = {
   makeArr,
   makeMap,
   makeObj,
+  makeSet,
   MathClamp,
   noContextMenu,
   normalizeUnicode,
@@ -195,6 +197,7 @@ export {
   makeArr,
   makeMap,
   makeObj,
+  makeSet,
   MathClamp,
   noContextMenu,
   normalizeUnicode,

src/shared/util.js

@@ -1135,6 +1135,7 @@ function _isValidExplicitDest(validRef, validName, dest) {
 const makeArr = () => [];
 const makeMap = () => new Map();
 const makeObj = () => Object.create(null);
+const makeSet = () => new Set();
 
 // See https://developer.mozilla.org/en-US/docs/Web/API/Blob/bytes#browser_compatibility
 if (
@@ -1197,6 +1198,7 @@ export {
   makeArr,
   makeMap,
   makeObj,
+  makeSet,
   MeshFigureType,
   normalizeUnicode,
   objectSize,

test/unit/pdf_spec.js

@@ -27,6 +27,7 @@ import {
   makeArr,
   makeMap,
   makeObj,
+  makeSet,
   normalizeUnicode,
   OPS,
   PasswordException,
@@ -115,6 +116,7 @@ const expectedAPI = Object.freeze({
   makeArr,
   makeMap,
   makeObj,
+  makeSet,
   MathClamp,
   noContextMenu,
   normalizeUnicode,

web/debugger.mjs

@@ -13,7 +13,7 @@
  * limitations under the License.
  */
 
-const { OPS } = globalThis.pdfjsLib || (await import("pdfjs-lib"));
+const { makeSet, OPS } = globalThis.pdfjsLib || (await import("pdfjs-lib"));
 
 const opMap = Object.create(null);
 for (const key in OPS) {
@@ -460,7 +460,7 @@ class Stepper {
     for (const [dependentIdx, { dependencies: ownDependencies }] of metadata) {
       for (const dependencyIdx of ownDependencies) {
         dependents
-          .getOrInsertComputed(dependencyIdx, () => new Set())
+          .getOrInsertComputed(dependencyIdx, makeSet)
           .add(dependentIdx);
       }
     }

web/pdfjs.js

@@ -47,6 +47,7 @@ const {
   makeArr,
   makeMap,
   makeObj,
+  makeSet,
   MathClamp,
   noContextMenu,
   normalizeUnicode,
@@ -111,6 +112,7 @@ export {
   makeArr,
   makeMap,
   makeObj,
+  makeSet,
   MathClamp,
   noContextMenu,
   normalizeUnicode,