Changeset 33291 for main

Timestamp:

2019-07-03T18:42:59+12:00 (5 years ago)

Author:

ak19

Message:

JavaScript has no block level vars, only function level and (file) globals. To make a confusing part of existing map-scripts.js easier to read for programmers who are used to block level var declarations, have rewritten some existing code to be more explicit in showing that variables declared in within a function are finction level scoped rather than block level scoped, as it's otherwise easy to mistake what's going on.

File:

• main/trunk/greenstone3/web/interfaces/default/js/map-scripts.js (modified) (3 diffs)

main/trunk/greenstone3/web/interfaces/default/js/map-scripts.js

@@ -571 +571 @@
         return;
     }
-    
+
+    var doc;
     var visibleMarkers = new Array();
     for(var i = 0; i < _docList.ids.length; i++)
     {
-        var doc = _docList.getDocByIndex(i);
+        //var doc = _docList.getDocByIndex(i);
+                     // NOTE: in JavaScript, "local" vars have function scope, not mere block level scope. Wherever declared inside a function, they get hoisted to function top.
+                     // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/var
+                     // But this feature is confusing, so have now declared var doc nearer to function top, at function level so outside current local block, and am assigning here:
+        doc = _docList.getDocByIndex(i);
         if(typeof doc.shapes !== 'undefined') {
             for(var x = 0; x < doc.shapes.length; x++) {
@@ -608 +613 @@
         }
 
-        var doc = visibleMarkers[_docList.loopIndex];
-        elem = gs.jqGet("div" + doc.nodeID); // TODO: this used to redefine elem by doing var elem = <....>
+        //var doc = visibleMarkers[_docList.loopIndex]; // See NOTE above.
+        doc = visibleMarkers[_docList.loopIndex];
+        elem = gs.jqGet("div" + doc.nodeID); // This used to redefine elem by doing var elem = <....>
+        // This worked because "If you re-declare a JavaScript variable, it will not lose its value." See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/var
         if(elem.length)
         {
@@ -617 +624 @@
         _docList.loopIndex ++;      
     }   
-    //console.log("@@@@ DOC:");
-    //console.log(doc);
-    
+
+    _gsDebug("@@@ loopThroughmarkers() - DOC:", doc);
+    
     if(doc.marker) {
         doc.marker.markerInfo.open(_map, doc.marker); // TODO: how does doc have a value here? Where is the value set at this block level?