documented and refactored restoreLineFolds function

src/extensions/default/CodeFolding/main.js

@@ -86,11 +86,33 @@ define(function (require, exports, module) {
       * @param {Editor} editor  the editor whose saved line folds should be restored
       */
     function restoreLineFolds(editor) {
-        function isInViewStateSelection(range, selection) {
+        /**
+         * Checks if the range from and to Pos is the same as the selection start and end Pos
+         * @param   {Object}  range     {from, to} where from and to are CodeMirror.Pos objects
+         * @param   {Object}  selection {start, end} where start and end are CodeMirror.Pos objects
+         * @returns {Boolean} true if the range and selection span the same region and false otherwise
+         */
+        function rangeEqualsSelection(range, selection) {
             return range.from.line === selection.start.line && range.from.ch === selection.start.ch &&
                 range.to.line === selection.end.line && range.to.ch === selection.end.ch;
         }
 
+        /**
+         * Checks if the range is equal to one of the selections in the viewState
+         * @param   {Object}  range     {from, to} where from and to are CodeMirror.Pos objects.
+         * @param   {Object}  viewState The current editor's ViewState object
+         * @returns {Boolean} true if the range is found in the list of selections or false if not.
+         */
+        function isInViewStateSelection(range, viewState) {
+            if (!viewState || !viewState.selections) {
+                return false;
+            }
+
+            return viewState.selections.some(function (selection) {
+                return rangeEqualsSelection(range, selection);
+            });
+        }
+
         var saveFolds = prefs.getSetting("saveFoldStates");
         if (!editor || !saveFolds) {
             return;
@@ -103,9 +125,7 @@ define(function (require, exports, module) {
         var nonSelectionFolds = {}, selectionFolds = {}, range;
         Object.keys(folds).forEach(function (line) {
             range = folds[line];
-            if (viewState.selections && viewState.selections.some(function (selection) {
-                    return isInViewStateSelection(range, selection);
-                })) {
+            if (isInViewStateSelection(range, viewState)) {
                 selectionFolds[line] = range;
             } else {
                 nonSelectionFolds[line] = range;