diff --git a/lib/child_process.js b/lib/child_process.js
index 6cce1b09e565..a78664c4abd4 100644
--- a/lib/child_process.js
+++ b/lib/child_process.js
@@ -59,22 +59,29 @@ function stdioStringToArray(option) {
 }
 
 exports.fork = function fork(modulePath /* , args, options */) {
-
   // Get options and args arguments.
   var execArgv;
-  var options = {};
-  var args = [];
-  var pos = 1;
-  if (pos < arguments.length && Array.isArray(arguments[pos])) {
-    args = arguments[pos++];
-  }
 
-  if (pos < arguments.length && arguments[pos] != null) {
-    if (typeof arguments[pos] !== 'object') {
-      throw new ERR_INVALID_ARG_VALUE(`arguments[${pos}]`, arguments[pos]);
-    }
+  var args = arguments[1];
+  var options = arguments[2];
+
+  if (Array.isArray(args)) {
+    args = args.slice(0);
+  } else if (options !== undefined &&
+    (args === undefined ||
+      args === null ||
+      typeof args !== 'object')
+  ) {
+    args = [];
+  } else {
+    options = args;
+    args = [];
+  }
 
-    options = util._extend({}, arguments[pos++]);
+  if (options === undefined || options === null) {
+    options = {};
+  } else if (typeof options !== 'object') {
+    throw new ERR_INVALID_ARG_VALUE('options', 'object', options);
   }
 
   // Prepare arguments for fork: