diff --git a/lib/model-helper.js b/lib/model-helper.js
index b818222..d165844 100644
--- a/lib/model-helper.js
+++ b/lib/model-helper.js
@@ -79,7 +79,7 @@ var modelHelper = module.exports = {
     out.type = modelHelper.getPropType(out.type);
 
     if (out.type === 'array') {
-      var hasItemType = typeof prop.type !== 'string' && prop.type.length;
+      var hasItemType = typeof prop.type !== 'string' && prop.type[0];
 
       if (hasItemType) {
         var arrayProp = prop.type[0];
diff --git a/test/model-helper.test.js b/test/model-helper.test.js
index e13da9f..d639390 100644
--- a/test/model-helper.test.js
+++ b/test/model-helper.test.js
@@ -89,6 +89,16 @@ describe('model-helper', function() {
         expect(prop).to.eql({ type: 'array' });
       });
 
+      it('converts [undefined] type', function() {
+        var def = getDefinition({
+          // This value is somehow provided by loopback-boot called from
+          // loopback-workspace.
+          array: [undefined]
+        });
+        var prop = def.properties.array;
+        expect(prop).to.eql({ type: 'array' });
+      });
+
       it('converts "array" type', function() {
         var def = getDefinition({
           array: 'array'