Fixed bug where .bind with incomplete data was removing fields from form.

lib/forms.js

@@ -29,7 +29,7 @@ exports.create = function (fields) {
             b.toHTML = f.toHTML;
             b.fields = {};
             Object.keys(f.fields).forEach(function (k) {
-                if (data[k] != null) {
+                if (data != null) {
                     b.fields[k] = f.fields[k].bind(data[k]);
                 }
             });

test/test-form.js

@@ -37,6 +37,34 @@ test('bind', function (t) {
     t.end();
 });
 
+test('bind with missing field in data keeps field in form', function (t) {
+    t.plan(12);
+    var form = forms.create({
+        field1: forms.fields.string(),
+        field2: forms.fields.string()
+    });
+    // unbound
+    t.equal(form.isValid, undefined);
+
+    // bound
+    var f = form.bind({field1: 'data one'});
+    t.equal(f.fields.field1.value, 'data one');
+    t.equal(f.fields.field1.data, 'data one');
+    t.equal(f.fields.field1.error, undefined);
+    t.equal(f.fields.field2.value, undefined);
+    t.equal(f.fields.field2.data, '');
+    t.equal(f.fields.field2.error, undefined);
+
+    t.ok(f.isValid instanceof Function);
+    t.equal(f.bind, undefined);
+    t.equal(f.handle, undefined);
+
+    t.deepEqual(f.data, {field1: 'data one', field2: ''});
+    t.ok(form !== f, 'bind returns new form object');
+
+    t.end();
+});
+
 test('validate', function (t) {
     t.plan(11);
     var form = forms.create({