[#330,model][s]: getFieldValue & getFieldValueUnrendered now return '' if field argument is null / undefined - fixes #330.

src/model.js

@@ -309,9 +309,11 @@ my.Record = Backbone.Model.extend({
   //
   // For the provided Field get the corresponding rendered computed data value
   // for this record.
+  //
+  // NB: if field is undefined a default '' value will be returned
   getFieldValue: function(field) {
     val = this.getFieldValueUnrendered(field);
-    if (field.renderer) {
+    if (field && !_.isUndefined(field.renderer)) {
       val = field.renderer(val, field, this.toJSON());
     }
     return val;
@@ -321,7 +323,12 @@ my.Record = Backbone.Model.extend({
   //
   // For the provided Field get the corresponding computed data value
   // for this record.
+  //
+  // NB: if field is undefined a default '' value will be returned
   getFieldValueUnrendered: function(field) {
+    if (!field) {
+      return '';
+    }
     var val = this.get(field.id);
     if (field.deriver) {
       val = field.deriver(val, field, this);

test/model.test.js

@@ -60,6 +60,20 @@ test('Field: type mapping', function () {
   });
 });
 
+test('Field: getFieldValue', function () {
+  var doc = new recline.Model.Record({
+    x: 12.3
+  });
+  var field = new recline.Model.Field({id: 'x'});
+  var out = doc.getFieldValue(field);
+  var exp = 12.3;
+  equal(out, exp);
+
+  // bad value 
+  var out = doc.getFieldValue();
+  equal(out, '');
+});
+
 test('Field: default renderers', function () {
   var doc = new recline.Model.Record({
     x: 12.3,
@@ -113,8 +127,10 @@ test('Field: custom deriver and renderer', function () {
   var field = new recline.Model.Field({id: 'computed', is_derived: true}, {
     deriver: deriver
   });
+  var out1 = doc.getFieldValueUnrendered(field);
   var out = doc.getFieldValue(field);
   var exp = 246;
+  equal(out1, exp);
   equal(out, exp);
 
   var field = new recline.Model.Field({id: 'x'}, {