fix($parse): support methods on falsy primitive types

e.g. zero, false, empty string

- fix tests to be executed with csp true
- fix cps (when more than 5 parts)

Author: vojtajina

src/ng/parse.js

@@ -695,7 +695,7 @@ function cspSafeGetterFn(key0, key1, key2, key3, key4) {
     var pathVal = (locals && locals.hasOwnProperty(key0)) ? locals : scope,
         promise;
 
-    if (!pathVal) return pathVal;
+    if (pathVal === null || pathVal === undefined) return pathVal;
 
     pathVal = pathVal[key0];
     if (pathVal && pathVal.then) {
@@ -706,7 +706,7 @@ function cspSafeGetterFn(key0, key1, key2, key3, key4) {
       }
       pathVal = pathVal.$$v;
     }
-    if (!key1 || !pathVal) return pathVal;
+    if (!key1 || pathVal === null || pathVal === undefined) return pathVal;
 
     pathVal = pathVal[key1];
     if (pathVal && pathVal.then) {
@@ -717,7 +717,7 @@ function cspSafeGetterFn(key0, key1, key2, key3, key4) {
       }
       pathVal = pathVal.$$v;
     }
-    if (!key2 || !pathVal) return pathVal;
+    if (!key2 || pathVal === null || pathVal === undefined) return pathVal;
 
     pathVal = pathVal[key2];
     if (pathVal && pathVal.then) {
@@ -728,7 +728,7 @@ function cspSafeGetterFn(key0, key1, key2, key3, key4) {
       }
       pathVal = pathVal.$$v;
     }
-    if (!key3 || !pathVal) return pathVal;
+    if (!key3 || pathVal === null || pathVal === undefined) return pathVal;
 
     pathVal = pathVal[key3];
     if (pathVal && pathVal.then) {
@@ -739,7 +739,7 @@ function cspSafeGetterFn(key0, key1, key2, key3, key4) {
       }
       pathVal = pathVal.$$v;
     }
-    if (!key4 || !pathVal) return pathVal;
+    if (!key4 || pathVal === null || pathVal === undefined) return pathVal;
 
     pathVal = pathVal[key4];
     if (pathVal && pathVal.then) {
@@ -767,18 +767,21 @@ function getterFn(path, csp) {
     fn = (pathKeysLength < 6)
         ? cspSafeGetterFn(pathKeys[0], pathKeys[1], pathKeys[2], pathKeys[3], pathKeys[4])
         : function(scope, locals) {
-          var i = 0, val;
+          var i = 0, val
           do {
             val = cspSafeGetterFn(
                     pathKeys[i++], pathKeys[i++], pathKeys[i++], pathKeys[i++], pathKeys[i++]
                   )(scope, locals);
+
             locals = undefined; // clear after first iteration
+            scope = val;
           } while (i < pathKeysLength);
-        };
+          return val;
+        }
   } else {
     var code = 'var l, fn, p;\n';
     forEach(pathKeys, function(key, index) {
-      code += 'if(!s) return s;\n' +
+      code += 'if(s === null || s === undefined) return s;\n' +
               'l=s;\n' +
               's='+ (index
                       // we simply dereference 's' on any .dot notation