Fix(exporter): fix #3642 export pdf in IE

Should download pdf similar to downloading a csv when in IE, whereas
all other browsers should open the pdf in place in a new tab (something
that pdfMake cannot do in IE).

Author: PaulL1

src/features/exporter/js/exporter.js

@@ -991,30 +991,31 @@
           ieVersion = this.isIE();
           var doc = pdfMake.createPdf(docDefinition);
           var blob;
+
           doc.getBuffer( function (buffer) {
             blob = new Blob([buffer]);
-          });
 
-          if (ieVersion && ieVersion < 10) {
-            var frame = D.createElement('iframe');
-            document.body.appendChild(frame);
+            if (ieVersion && ieVersion < 10) {
+              var frame = D.createElement('iframe');
+              document.body.appendChild(frame);
 
-            frame.contentWindow.document.open("text/html", "replace");
-            frame.contentWindow.document.write(blob);
-            frame.contentWindow.document.close();
-            frame.contentWindow.focus();
-            frame.contentWindow.document.execCommand('SaveAs', true, fileName);
+              frame.contentWindow.document.open("text/html", "replace");
+              frame.contentWindow.document.write(blob);
+              frame.contentWindow.document.close();
+              frame.contentWindow.focus();
+              frame.contentWindow.document.execCommand('SaveAs', true, fileName);
 
-            document.body.removeChild(frame);
-            return true;
-          }
+              document.body.removeChild(frame);
+              return true;
+            }
 
-          // IE10+
-          if (navigator.msSaveBlob) {
-            return navigator.msSaveBlob(
-              blob, fileName
-            );
-          }
+            // IE10+
+            if (navigator.msSaveBlob) {
+              return navigator.msSaveBlob(
+                blob, fileName
+              );
+            }
+          });
         },