From b7367a2a8c12a3122adb42cac98960140247772e Mon Sep 17 00:00:00 2001
From: Ingvar Stepanyan <me@rreverser.com>
Date: Sun, 26 Oct 2014 20:21:39 +0200
Subject: [PATCH] Make setOptions non-destructive for original object.

---
 acorn.js | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/acorn.js b/acorn.js
index 14648d36a1..e6658d8c64 100644
--- a/acorn.js
+++ b/acorn.js
@@ -135,9 +135,9 @@
   };
 
   function setOptions(opts) {
-    options = opts || {};
-    for (var opt in defaultOptions) if (!has(options, opt))
-      options[opt] = defaultOptions[opt];
+    options = {};
+    for (var opt in defaultOptions)
+      options[opt] = has(opts, opt) ? opts[opt] : defaultOptions[opt];
     sourceFile = options.sourceFile || null;
     if (isArray(options.onToken)) {
       var tokens = options.onToken;