clean up keyedContainer for possibly missing array

Author: alexcjohnson

src/lib/keyed_container.js

@@ -33,32 +33,44 @@ var UNSET = 4;
 module.exports = function keyedContainer(baseObj, path, keyName, valueName) {
     keyName = keyName || 'name';
     valueName = valueName || 'value';
-    var i, arr;
+    var i, arr, baseProp;
     var changeTypes = {};
 
-    if(path && path.length) { arr = nestedProperty(baseObj, path).get();
+    if(path && path.length) {
+        baseProp = nestedProperty(baseObj, path);
+        arr = baseProp.get();
     } else {
         arr = baseObj;
     }
 
     path = path || '';
-    arr = arr || [];
 
     // Construct an index:
     var indexLookup = {};
-    for(i = 0; i < arr.length; i++) {
-        indexLookup[arr[i][keyName]] = i;
+    if(arr) {
+        for(i = 0; i < arr.length; i++) {
+            indexLookup[arr[i][keyName]] = i;
+        }
     }
 
     var isSimpleValueProp = SIMPLE_PROPERTY_REGEX.test(valueName);
 
     var obj = {
-        // NB: this does not actually modify the baseObj
         set: function(name, value) {
             var changeType = value === null ? UNSET : NONE;
 
+            // create the base array if necessary
+            if(!arr) {
+                if(!baseProp || changeType === UNSET) return;
+
+                arr = [];
+                baseProp.set(arr);
+            }
+
             var idx = indexLookup[name];
             if(idx === undefined) {
+                if(changeType === UNSET) return;
+
                 changeType = changeType | BOTH;
                 idx = arr.length;
                 indexLookup[name] = idx;
@@ -86,6 +98,8 @@ module.exports = function keyedContainer(baseObj, path, keyName, valueName) {
             return obj;
         },
         get: function(name) {
+            if(!arr) return;
+
             var idx = indexLookup[name];
 
             if(idx === undefined) {

test/jasmine/tests/lib_test.js

@@ -1742,6 +1742,51 @@ describe('Test lib.js:', function() {
     });
 
     describe('keyedContainer', function() {
+        describe('with no existing container', function() {
+            it('creates a named container only when setting a value', function() {
+                var container = {};
+                var kCont = Lib.keyedContainer(container, 'styles');
+
+                expect(kCont.get('name1')).toBeUndefined();
+                expect(container).toEqual({});
+
+                kCont.set('name1', null);
+                expect(container).toEqual({});
+
+                kCont.set('name1', 'value1');
+                expect(container).toEqual({
+                    styles: [{name: 'name1', value: 'value1'}]
+                });
+                expect(kCont.get('name1')).toBe('value1');
+                expect(kCont.get('name2')).toBeUndefined();
+            });
+        });
+
+        describe('with no path', function() {
+            it('adds elements just like when there is a path', function() {
+                var arr = [];
+                var kCont = Lib.keyedContainer(arr);
+
+                expect(kCont.get('name1')).toBeUndefined();
+                expect(arr).toEqual([]);
+
+                kCont.set('name1', null);
+                expect(arr).toEqual([]);
+
+                kCont.set('name1', 'value1');
+                expect(arr).toEqual([{name: 'name1', value: 'value1'}]);
+                expect(kCont.get('name1')).toBe('value1');
+                expect(kCont.get('name2')).toBeUndefined();
+            });
+
+            it('does not barf if the array is missing', function() {
+                var kCont = Lib.keyedContainer();
+                kCont.set('name1', null);
+                kCont.set('name1', 'value1');
+                expect(kCont.get('name1')).toBeUndefined();
+            });
+        });
+
         describe('with a filled container', function() {
             var container, carr;