1 files changed, 25 insertions, 0 deletions
diff --git a/deps/npm/lib/install/realize-shrinkwrap-specifier.js b/deps/npm/lib/install/realize-shrinkwrap-specifier.js
new file mode 100644
index 0000000000..0c491a6028
--- /dev/null
+++ b/deps/npm/lib/install/realize-shrinkwrap-specifier.js
@@ -0,0 +1,25 @@
+'use strict'
+var realizePackageSpecifier = require('realize-package-specifier')
+var isRegistrySpecifier = require('./is-registry-specifier.js')
+
+module.exports = function (name, sw, where, cb) {
+  function lookup (ver, cb) {
+    realizePackageSpecifier(name + '@' + ver, where, cb)
+  }
+  if (sw.resolved) {
+    return lookup(sw.resolved, cb)
+  } else if (sw.from) {
+    return lookup(sw.from, function (err, spec) {
+      if (err || isRegistrySpecifier(spec)) {
+        return thenUseVersion()
+      } else {
+        return cb(null, spec)
+      }
+    })
+  } else {
+    return thenUseVersion()
+  }
+  function thenUseVersion () {
+    lookup(sw.version, cb)
+  }
+}