fix iteration over object with inherited properties (#2068)

fixes #2055

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/minify.js b/lib/minify.js
index 16f5b189..cc638be3 100644
--- a/lib/minify.js
+++ b/lib/minify.js
@@ -86,7 +86,7 @@ function minify(files, options) {
             }
             options.parse = options.parse || {};
             options.parse.toplevel = null;
-            for (var name in files) {
+            for (var name in files) if (HOP(files, name)) {
                 options.parse.filename = name;
                 options.parse.toplevel = parse(files[name], options.parse);
                 if (options.sourceMap && options.sourceMap.content == "inline") {
@@ -134,7 +134,7 @@ function minify(files, options) {
                 if (options.sourceMap.includeSources) {
                     if (files instanceof AST_Toplevel) {
                         throw new Error("original source content unavailable");
-                    } else for (var name in files) {
+                    } else for (var name in files) if (HOP(files, name)) {
                         options.output.source_map.get().setSourceContent(name, files[name]);
                     }
                 }