diff --git a/lib/utils.js b/lib/utils.js
index e28c26a..d102d63 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -103,6 +103,10 @@ function normalizeQueryConfig (config, values, callback) {
 }
 
 module.exports = {
-  prepareValue: prepareValue,
+  prepareValue: function prepareValueWrapper (value) {
+    //this ensures that extra arguments do not get passed into prepareValue
+    //by accident, eg: from calling values.map(utils.prepareValue)
+    return prepareValue(value);
+  },
   normalizeQueryConfig: normalizeQueryConfig
 };
diff --git a/test/unit/utils-tests.js b/test/unit/utils-tests.js
index 116dfdd..b0e3e91 100644
--- a/test/unit/utils-tests.js
+++ b/test/unit/utils-tests.js
@@ -171,3 +171,14 @@ test('prepareValue: objects with circular toPostgres rejected', function() {
   }
   throw new Error("Expected prepareValue to throw exception");
 });
+
+test('prepareValue: can safely be used to map an array of values including those with toPostgres functions', function() {
+  var customType = {
+    toPostgres: function() {
+      return "zomgcustom!";
+    }
+  };
+  var values = [1, "test", customType]
+  var out = values.map(utils.prepareValue)
+  assert.deepEqual(out, [1, "test", "zomgcustom!"])
+})