From 567cc6730d8627a5eeff57b0e51b42afbf416caf Mon Sep 17 00:00:00 2001
From: indexzero <charlie.robbins@gmail.com>
Date: Wed, 22 Jul 2015 00:05:28 -0700
Subject: [PATCH 1/2] [refactor] Simplify `registrar` function.

---
 index.js | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/index.js b/index.js
index dfaa0fe..5abaa80 100644
--- a/index.js
+++ b/index.js
@@ -22,20 +22,19 @@ function Understudy() {
 
 function registrar(property) {
   return function (action, callback) {
-    if (typeof action === 'string') {
-      if (typeof callback === 'function') {
-        this[property] || (this[property] = {});
-        this[property][action] || (this[property][action] = []);
-        var interceptors = this[property][action];
-        interceptors[interceptors.length] = callback;
-        return this;
-      }
-      else {
-        throw new Error('callback must be a function');
-      }
+    if (typeof action !== 'string') {
+      throw new Error('event must be a string');
+    } else if (typeof callback !== 'function') {
+      throw new Error('callback must be a function');
     }
-    throw new Error('event must be a string');
-  }
+
+    this[property] = this[property] || {};
+    var interceptors = this[property][action]
+      = this[property][action] || [];
+
+    interceptors.push(callback);
+    return this;
+  };
 }
 
 function perform(action /* , args..., performFn, callback*/) {

From b7b49ce8ab8e1667debe2206b064f4d37bdece91 Mon Sep 17 00:00:00 2001
From: indexzero <charlie.robbins@gmail.com>
Date: Wed, 22 Jul 2015 01:38:12 -0700
Subject: [PATCH 2/2] [api] Expose the registrar function and allow for
 `unshift` as well as `push`.

---
 index.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/index.js b/index.js
index 5abaa80..0470853 100644
--- a/index.js
+++ b/index.js
@@ -17,10 +17,13 @@ function Understudy() {
   this.before = registrar('_before_interceptors');
   this._before_interceptors = null;
   this._after_interceptors = null;
+  this._interceptor_registrar = registrar;
   return this;
 }
 
-function registrar(property) {
+function registrar(property, fn) {
+  fn = fn || 'push';
+
   return function (action, callback) {
     if (typeof action !== 'string') {
       throw new Error('event must be a string');
@@ -32,7 +35,7 @@ function registrar(property) {
     var interceptors = this[property][action]
       = this[property][action] || [];
 
-    interceptors.push(callback);
+    interceptors[fn](callback);
     return this;
   };
 }