Merge pull request #9034 from Snuffleupagus/javascript-null

[api-major] Change `getJavaScript` to return `null`, rather than an empty Array, when no JavaScript exists

src/core/obj.js

@@ -371,7 +371,7 @@ var Catalog = (function CatalogClosure() {
       var xref = this.xref;
       var obj = this.catDict.get('Names');
 
-      var javaScript = [];
+      let javaScript = null;
       function appendIfJavaScriptDict(jsDict) {
         var type = jsDict.get('S');
         if (!isName(type, 'JavaScript')) {
@@ -383,6 +383,9 @@ var Catalog = (function CatalogClosure() {
         } else if (!isString(js)) {
           return;
         }
+        if (!javaScript) {
+          javaScript = [];
+        }
         javaScript.push(stringToPDFString(js));
       }
       if (obj && obj.has('JavaScript')) {
@@ -407,6 +410,9 @@ var Catalog = (function CatalogClosure() {
           // but is supported by many PDF readers/writers (including Adobe's).
           var action = openactionDict.get('N');
           if (isName(action, 'Print')) {
+            if (!javaScript) {
+              javaScript = [];
+            }
             javaScript.push('print({});');
           }
         } else {

src/display/api.js

@@ -574,10 +574,10 @@ var PDFDocumentProxy = (function PDFDocumentProxyClosure() {
       return this.transport.getAttachments();
     },
     /**
-     * @return {Promise} A promise that is resolved with an array of all the
+     * @return {Promise} A promise that is resolved with an {Array} of all the
-     * JavaScript strings in the name tree.
+     * JavaScript strings in the name tree, or `null` if no JavaScript exists.
      */
-    getJavaScript: function PDFDocumentProxy_getJavaScript() {
+    getJavaScript() {
       return this.transport.getJavaScript();
     },
     /**

test/unit/api_spec.js

@@ -683,7 +683,7 @@ describe('api', function() {
     it('gets javascript', function(done) {
       var promise = doc.getJavaScript();
       promise.then(function (data) {
-        expect(data).toEqual([]);
+        expect(data).toEqual(null);
         done();
       }).catch(function (reason) {
         done.fail(reason);

web/app.js

@@ -1035,10 +1035,12 @@ let PDFViewerApplication = {
         return;
       }
       pdfDocument.getJavaScript().then((javaScript) => {
-        if (javaScript.length) {
+        if (!javaScript) {
+          return;
+        }
         console.warn('Warning: JavaScript is not supported');
         this.fallback(UNSUPPORTED_FEATURES.javaScript);
-        }
+
         // Hack to support auto printing.
         let regex = /\bprint\s*\(/;
         for (let i = 0, ii = javaScript.length; i < ii; i++) {