1 files changed, 29 insertions, 0 deletions
diff --git a/addon-sdk/source/lib/sdk/lang/functional/helpers.js b/addon-sdk/source/lib/sdk/lang/functional/helpers.js
new file mode 100644
index 000000000..60f4e3300
--- /dev/null
+++ b/addon-sdk/source/lib/sdk/lang/functional/helpers.js
@@ -0,0 +1,29 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Disclaimer: Some of the functions in this module implement APIs from
+// Jeremy Ashkenas's http://underscorejs.org/ library and all credits for
+// those goes to him.
+
+"use strict";
+
+module.metadata = {
+  "stability": "unstable"
+}
+
+const arity = f => f.arity || f.length;
+exports.arity = arity;
+
+const name = f => f.displayName || f.name;
+exports.name = name;
+
+const derive = (f, source) => {
+  f.displayName = name(source);
+  f.arity = arity(source);
+  return f;
+};
+exports.derive = derive;
+
+const invoke = (callee, params, self) => callee.apply(self, params);
+exports.invoke = invoke;