Allow access to prototype properties

Author: fredludlow

src/sprintf.js

@@ -41,7 +41,7 @@
                 if (ph.keys) { // keyword argument
                     arg = argv[cursor]
                     for (k = 0; k < ph.keys.length; k++) {
-                        if (!arg.hasOwnProperty(ph.keys[k])) {
+                        if (arg[ph.keys[k]] === undefined) {
                             throw new Error(sprintf('[sprintf] property "%s" does not exist', ph.keys[k]))
                         }
                         arg = arg[ph.keys[k]]

test/test_validation.js

@@ -58,3 +58,14 @@ describe('sprintfjs', function() {
         })
     })
 })
+
+describe('sprintfjs-prototype', function() {
+
+    function Klass() {}
+    Klass.prototype = {
+        get x() { return 2 }
+    }
+    it('Prototype properties should not cause an error', function() {
+        should_not_throw('%(x)s', new Klass())
+    })
+})