Replaces literal {} created lookup tables with Object.create

Author: yurydelendik

src/core/chunked_stream.js

@@ -313,9 +313,9 @@ var ChunkedStreamManager = (function ChunkedStreamManagerClosure() {
 
     this.currRequestId = 0;
 
-    this.chunksNeededByRequest = {};
-    this.requestsByChunk = {};
-    this.promisesByRequest = {};
+    this.chunksNeededByRequest = Object.create(null);
+    this.requestsByChunk = Object.create(null);
+    this.promisesByRequest = Object.create(null);
     this.progressiveDataLength = 0;
 
     this._loadedStreamCapability = createPromiseCapability();
@@ -341,9 +341,9 @@ var ChunkedStreamManager = (function ChunkedStreamManagerClosure() {
     _requestChunks: function ChunkedStreamManager_requestChunks(chunks) {
       var requestId = this.currRequestId++;
 
-      var chunksNeeded;
       var i, ii;
-      this.chunksNeededByRequest[requestId] = chunksNeeded = {};
+      var chunksNeeded = Object.create(null);
+      this.chunksNeededByRequest[requestId] = chunksNeeded;
       for (i = 0, ii = chunks.length; i < ii; i++) {
         if (!this.stream.hasChunk(chunks[i])) {
           chunksNeeded[chunks[i]] = true;

src/core/evaluator.js

@@ -731,7 +731,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
 
       var self = this;
       var xref = this.xref;
-      var imageCache = {};
+      var imageCache = Object.create(null);
 
       assert(operatorList);
 
@@ -1054,7 +1054,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
 
       // The xobj is parsed iff it's needed, e.g. if there is a `DO` cmd.
       var xobjs = null;
-      var xobjsCache = {};
+      var xobjsCache = Object.create(null);
 
       var preprocessor = new EvaluatorPreprocessor(stream, xref, stateManager);
 
@@ -2093,7 +2093,7 @@ var TranslatedFont = (function TranslatedFontClosure() {
       var charProcs = this.dict.get('CharProcs').getAll();
       var fontResources = this.dict.get('Resources') || resources;
       var charProcKeys = Object.keys(charProcs);
-      var charProcOperatorList = {};
+      var charProcOperatorList = Object.create(null);
       for (var i = 0, n = charProcKeys.length; i < n; ++i) {
         loadCharProcsPromise = loadCharProcsPromise.then(function (key) {
           var glyphStream = charProcs[key];
@@ -2147,7 +2147,7 @@ var OperatorList = (function OperatorListClosure() {
     this.messageHandler = messageHandler;
     this.fnArray = [];
     this.argsArray = [];
-    this.dependencies = {};
+    this.dependencies = Object.create(null);
     this._totalLength = 0;
     this.pageIndex = pageIndex;
     this.intent = intent;
@@ -2227,7 +2227,7 @@ var OperatorList = (function OperatorListClosure() {
         pageIndex: this.pageIndex,
         intent: this.intent
       }, transfers);
-      this.dependencies = {};
+      this.dependencies = Object.create(null);
       this.fnArray.length = 0;
       this.argsArray.length = 0;
     }

src/core/font_renderer.js

@@ -609,7 +609,7 @@ var FontRendererFactory = (function FontRendererFactoryClosure() {
   var noop = '';
 
   function CompiledFont(fontMatrix) {
-    this.compiledGlyphs = {};
+    this.compiledGlyphs = Object.create(null);
     this.fontMatrix = fontMatrix;
   }
   CompiledFont.prototype = {