Merge pull request #187 from twitter/null_sections

Treat null values as key hits to match Mustache.rb and Hogan 2.0

lib/template.js

@@ -146,7 +146,7 @@ var Hogan = {};
       } else {
         for (var i = 1; i < names.length; i++) {
           found = findInScope(names[i], val, doModelGet);
-          if (found != null) {
+          if (found !== undefined) {
             cx = val;
             val = found;
           } else {
@@ -178,7 +178,7 @@ var Hogan = {};
       for (var i = ctx.length - 1; i >= 0; i--) {
         v = ctx[i];
         val = findInScope(key, v, doModelGet);
-        if (val != null) {
+        if (val !== undefined) {
           found = true;
           break;
         }
@@ -262,11 +262,11 @@ var Hogan = {};
 
   //Find a key in an object
   function findInScope(key, scope, doModelGet) {
-    var val, checkVal;
+    var val;
 
     if (scope && typeof scope == 'object') {
 
-      if (scope[key] != null) {
+      if (scope[key] !== undefined) {
         val = scope[key];
 
       // try lookup with get for backbone or similar model data

test/index.js

@@ -499,6 +499,36 @@ test("Undefined Return Value From Lambda", function() {
   is(s, "abcdef", "deal with undefined return values from lambdas.")
 });
 
+test("Sections with null values are treated as key hits", function() {
+  var text = "{{#obj}}{{#sub}}{{^test}}ok{{/test}}{{/sub}}{{/obj}}";
+  var t = Hogan.compile(text);
+  var context = {
+    obj: {
+      test: true,
+      sub: {
+        test: null
+      }
+    }
+  }
+  var s = t.render(context);
+  is(s, "ok");
+});
+
+test("Sections with undefined values are treated as key misses", function() {
+  var text = "{{#obj}}{{#sub}}{{#test}}ok{{/test}}{{/sub}}{{/obj}}";
+  var t = Hogan.compile(text);
+  var context = {
+    obj: {
+      test: true,
+      sub: {
+        test: undefined
+      }
+    }
+  }
+  var s = t.render(context);
+  is(s, "ok");
+});
+
 test("Section Extensions", function() {
   var text = "Test {{_//|__foo}}bar{{/foo}}";
   var options = {sectionTags:[{o:'_//|__foo', c:'foo'}]};