diff --git a/src/js/utils.js b/src/js/utils.js
index 6e00094..886b596 100644
--- a/src/js/utils.js
+++ b/src/js/utils.js
@@ -18,9 +18,9 @@ utils.errors = {
 };
 
 utils.validArrayOfStrings = (val) => {
-  return (val && Array.isArray(val) && val.length > 0 && !val.find(i => !i.length || typeof i !== 'string'));
+  return (Array.isArray(val) && val.length > 0 && val.every(utils.validString));
 };
 
 utils.validString = (val) => {
-  return (val && val.length && typeof val === 'string');
+  return (typeof val === 'string' && val.length > 0);
 };
diff --git a/test/utils.js b/test/utils.js
new file mode 100644
index 0000000..697f31c
--- /dev/null
+++ b/test/utils.js
@@ -0,0 +1,41 @@
+import { utils } from '../www/index-ios';
+import assert from 'assert';
+
+describe('utils', () => {
+  describe('validArrayOfStrings', () => {
+    it('should return true on a valid non-empty string array', () => {
+      assert(utils.validArrayOfStrings(['product1']) === true);
+      assert(utils.validArrayOfStrings(['product1', 'product2']) === true);
+    });
+
+    it('should return false on a invalid non-empty string array', () => {
+      assert(utils.validArrayOfStrings([]) === false);
+      assert(utils.validArrayOfStrings(['']) === false);
+      assert(utils.validArrayOfStrings([null]) === false);
+      assert(utils.validArrayOfStrings([undefined]) === false);
+      assert(utils.validArrayOfStrings(['product1', null]) === false);
+      assert(utils.validArrayOfStrings(['product1', '']) === false);
+      assert(utils.validArrayOfStrings(null) === false);
+      assert(utils.validArrayOfStrings() === false);
+      assert(utils.validArrayOfStrings(false) === false);
+      assert(utils.validArrayOfStrings('product1') === false);
+      assert(utils.validArrayOfStrings(123) === false);
+    });
+  });
+
+  describe('validString', () => {
+    it('should return true on a valid non-empty string', () => {
+      assert(utils.validString('abc') === true);
+    });
+
+    it('should return false on anyting else', () => {
+      assert(utils.validString() === false);
+      assert(utils.validString(null) === false);
+      assert(utils.validString('') === false);
+      assert(utils.validString(123) === false);
+      assert(utils.validString(true) === false);
+      assert(utils.validString([]) === false);
+      assert(utils.validString({}) === false);
+    });
+  });
+});
diff --git a/www/index-android.js b/www/index-android.js
index 4f4ade7..ac92fec 100644
--- a/www/index-android.js
+++ b/www/index-android.js
@@ -58,13 +58,11 @@ utils.errors = {
 };
 
 utils.validArrayOfStrings = function (val) {
-  return val && Array.isArray(val) && val.length > 0 && !val.find(function (i) {
-    return !i.length || typeof i !== 'string';
-  });
+  return Array.isArray(val) && val.length > 0 && val.every(utils.validString);
 };
 
 utils.validString = function (val) {
-  return val && val.length && typeof val === 'string';
+  return typeof val === 'string' && val.length > 0;
 };
 'use strict';
 
diff --git a/www/index-ios.js b/www/index-ios.js
index 7eb5566..1cc2821 100644
--- a/www/index-ios.js
+++ b/www/index-ios.js
@@ -20,13 +20,11 @@ utils.errors = {
 };
 
 utils.validArrayOfStrings = function (val) {
-  return val && Array.isArray(val) && val.length > 0 && !val.find(function (i) {
-    return !i.length || typeof i !== 'string';
-  });
+  return Array.isArray(val) && val.length > 0 && val.every(utils.validString);
 };
 
 utils.validString = function (val) {
-  return val && val.length && typeof val === 'string';
+  return typeof val === 'string' && val.length > 0;
 };
 'use strict';