From 11387ab4789554ccd73dcee8fe9403ad78146caf Mon Sep 17 00:00:00 2001
From: stoeffel <schtoeffel@gmail.com>
Date: Mon, 23 Feb 2015 12:51:39 +0100
Subject: [PATCH] add arity example

---
 readme.md | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/readme.md b/readme.md
index d92a59c..d7eb6f3 100644
--- a/readme.md
+++ b/readme.md
@@ -5,19 +5,29 @@
 __Let's try and define these with examples, this is a WIP please feel free to send PR ;)__
 
 
-## Arity 
+## Arity
+
+> The number of arguments a function takes.
+
+```js
+const sum = (a, b) => a + b;
+
+const arity = sum.length;
+console.log(arity);
+// => 2
+// The arity of sum is 2
+```
+
+
+## Purity
 
 ---
 
-## Purity 
+## Side effects
 
 ---
 
-## Side effects 
-
----
-
-## Idempotency 
+## Idempotency
 
 ---