1 files changed, 19 insertions, 13 deletions
diff --git a/deps/npm/lib/install/copy-tree.js b/deps/npm/lib/install/copy-tree.js
index 67a9c687a2..a5b558cf59 100644
--- a/deps/npm/lib/install/copy-tree.js
+++ b/deps/npm/lib/install/copy-tree.js
@@ -1,25 +1,31 @@
 'use strict'
-
-module.exports = function (tree) {
-  return copyTree(tree, {})
+var createNode = require('./node.js').create
+module.exports = function (tree, filter) {
+  return copyTree(tree, {}, filter)
 }
 
-function copyTree (tree, cache) {
-  if (cache[tree.path]) return cache[tree.path]
-  var newTree = cache[tree.path] = Object.create(tree)
-  copyModuleList(newTree, 'children', cache)
+function copyTree (tree, cache, filter) {
+  if (filter && !filter(tree)) { return null }
+  if (cache[tree.path]) { return cache[tree.path] }
+  var newTree = cache[tree.path] = createNode(Object.assign({}, tree))
+  copyModuleList(newTree, 'children', cache, filter)
   newTree.children.forEach(function (child) {
     child.parent = newTree
   })
-  copyModuleList(newTree, 'requires', cache)
-  copyModuleList(newTree, 'requiredBy', cache)
+  copyModuleList(newTree, 'requires', cache, filter)
+  copyModuleList(newTree, 'requiredBy', cache, filter)
   return newTree
 }
 
-function copyModuleList (tree, key, cache) {
+function copyModuleList (tree, key, cache, filter) {
   var newList = []
-  tree[key].forEach(function (child) {
-    newList.push(copyTree(child, cache))
-  })
+  if (tree[key]) {
+    tree[key].forEach(function (child) {
+      const copy = copyTree(child, cache, filter)
+      if (copy) {
+        newList.push(copy)
+      }
+    })
+  }
   tree[key] = newList
 }