handle firstOf undefined correctly

lib/jsonapter.js

@@ -244,7 +244,7 @@ var prototype = {
         for (var i = 0; i < templateFirstOf.length; ++i) {
             var t = templateFirstOf[i];
             var value = this.evaluateValue(t, input, parent, params, arrayIndex, arraySize, options);
-            if (value !== null) {
+            if (!_.isNil(value)) {
                 return value;
             }
         }

package.json

@@ -1,6 +1,6 @@
 {
     "name": "jsonapter",
-    "version": "2.0.6",
+    "version": "2.0.7",
     "description": "Template based JSON to JSON transformer",
     "main": "./index.js",
     "directories": {

test/test-firstOf.js

@@ -5,6 +5,7 @@ var chai = require('chai');
 var json2json = require('../index');
 
 var case_0 = require('./test_cases/case-firstOf-0');
+var case_1 = require('./test_cases/case-firstOf-1');
 
 var expect = chai.expect;
 
@@ -19,4 +20,13 @@ describe('firtOf', function () {
             expect(actual).to.deep.equal(case_0.expecteds[i]);
         }
     });
+
+    it('case-firstOf-1: undefined output', function () {
+        var template = case_1.template;
+        var n = case_1.inputs.length;
+        for (var i = 0; i < n; ++i) {
+            var actual = engine.run(template, case_1.inputs[i]);
+            expect(actual).to.deep.equal(case_1.expecteds[i]);
+        }
+    });
 });

test/test_cases/case-firstOf-1.js

@@ -0,0 +1,39 @@
+"use strict";
+
+exports.template = {
+    content: {
+        item: {
+            firstOf: [{
+                value: function (input) {
+                    if (input.startsWith('a')) {
+                        return input + ' 1st';
+                    }
+                }
+            }, {
+                value: function (input) {
+                    if (input.startsWith('b')) {
+                        return input + ' 2nd';
+                    }
+                }
+            }, {
+                value: function (input) {
+                    if (input.startsWith('c')) {
+                        return input + ' 3rd';
+                    }
+                }
+            }]
+        }
+    },
+    dataKey: 'prop'
+};
+
+exports.inputs = [];
+exports.expecteds = [];
+
+exports.inputs[0] = { prop: 'and' };
+exports.inputs[1] = { prop: 'but' };
+exports.inputs[2] = { prop: 'cal' };
+
+exports.expecteds[0] = { item: 'and 1st' };
+exports.expecteds[1] = { item: 'but 2nd' };
+exports.expecteds[2] = { item: 'cal 3rd' };