1 files changed, 27 insertions, 0 deletions
diff --git a/deps/node/deps/npm/lib/install/is-extraneous.js b/deps/node/deps/npm/lib/install/is-extraneous.js
new file mode 100644
index 00000000..a6477c23
--- /dev/null
+++ b/deps/node/deps/npm/lib/install/is-extraneous.js
@@ -0,0 +1,27 @@
+'use strict'
+module.exports = isExtraneous
+
+function isExtraneous (tree) {
+  var result = !isNotExtraneous(tree)
+  return result
+}
+
+function topHasNoPjson (tree) {
+  var top = tree
+  while (!top.isTop) top = top.parent
+  return top.error
+}
+
+function isNotExtraneous (tree, isCycle) {
+  if (!isCycle) isCycle = {}
+  if (tree.isTop || tree.userRequired) {
+    return true
+  } else if (isCycle[tree.path]) {
+    return topHasNoPjson(tree)
+  } else {
+    isCycle[tree.path] = true
+    return tree.requiredBy && tree.requiredBy.some(function (node) {
+      return isNotExtraneous(node, Object.create(isCycle))
+    })
+  }
+}