1 files changed, 3 insertions, 3 deletions
diff --git a/deps/npm/lib/install/flatten-tree.js b/deps/npm/lib/install/flatten-tree.js
index b6ceb30f2f..56282b771d 100644
--- a/deps/npm/lib/install/flatten-tree.js
+++ b/deps/npm/lib/install/flatten-tree.js
@@ -8,19 +8,19 @@ module.exports.flatNameFromTree = flatNameFromTree
 
 function flattenTree (tree) {
   validate('O', arguments)
-  var seen = {}
+  var seen = new Set()
   var flat = {}
   var todo = [[tree, '/']]
   while (todo.length) {
     var next = todo.shift()
     var pkg = next[0]
-    seen[pkg.path] = true
+    seen.add(pkg)
     var path = next[1]
     flat[path] = pkg
     if (path !== '/') path += '/'
     for (var ii = 0; ii < pkg.children.length; ++ii) {
       var child = pkg.children[ii]
-      if (!seen[child.path]) {
+      if (!seen.has(child)) {
         todo.push([child, flatName(path, child)])
       }
     }