From c3cf89525c268db389162aec91dfe50ec455b861 Mon Sep 17 00:00:00 2001
From: Thomas Parisot <thomas.parisot@bbc.co.uk>
Date: Thu, 23 Jan 2014 16:40:31 +0000
Subject: [PATCH 1/2] Revealing `availableWidths` bug through tests.

---
 test/unit/core.js | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/test/unit/core.js b/test/unit/core.js
index 7f89146..5647379 100644
--- a/test/unit/core.js
+++ b/test/unit/core.js
@@ -124,14 +124,15 @@ describe('Imager.js', function () {
 
         it('can be a function computing a value for you', function (done) {
             // this example will always compute sizes 8 pixels by 8 pixels
-            // we need to stub it for now as events are triggered automatically and generates exceptions we can escape
-            var imgr = new Imager();
+            var imgr = new Imager({
+              onResize: false,
+              lazyload: false,
+              availableWidths: function (image) {
+                return image.clientWidth - image.clientWidth % 8 + (1 * (image.clientWidth % 8 ? 8 : 0));
+              }
+            });
 
             setTimeout(function () {
-                imgr.availableWidths = function (image) {
-                    return image.clientWidth - image.clientWidth % 8 + (1 * (image.clientWidth % 8 ? 8 : 0));
-                };
-
                 var img = { clientWidth: 320 };
                 var spy = sandbox.spy(imgr, 'availableWidths');
 

From 679a2c293500c0e852d28852ba1c4eb958560c93 Mon Sep 17 00:00:00 2001
From: Thomas Parisot <thomas.parisot@bbc.co.uk>
Date: Thu, 23 Jan 2014 16:41:50 +0000
Subject: [PATCH 2/2] Proper initialisation of Imager instance
 `availableWidths` option.

- removed `isArray` function
- bootstrapping instance variables
- array/object paths
---
 Imager.js | 33 +++++++++++++++------------------
 1 file changed, 15 insertions(+), 18 deletions(-)

diff --git a/Imager.js b/Imager.js
index 849e524..c6522a5 100644
--- a/Imager.js
+++ b/Imager.js
@@ -2,7 +2,7 @@
 
     'use strict';
 
-    var defaultWidths, getKeys, isArray, nextTick, addEvent;
+    var defaultWidths, getKeys, nextTick, addEvent;
 
     nextTick = window.requestAnimationFrame ||
                window.mozRequestAnimationFrame ||
@@ -53,10 +53,6 @@
         return keys;
     };
 
-    isArray = function isArray (object) {
-        return Object.prototype.toString.call(object) === '[object Array]';
-    };
-
 
     /*
         Construct a new Imager instance, passing an optional configuration object.
@@ -119,24 +115,25 @@
         this.lazyload         = opts.hasOwnProperty('lazyload') ? opts.lazyload : false;
         this.scrolled         = false;
         this.availablePixelRatios = opts.availablePixelRatios || [1, 2];
+        this.availableWidths  = opts.availableWidths || defaultWidths;
+        this.widthMap         = {};
         this.refreshPixelRatio();
 
-        if (opts.availableWidths === undefined) {
-            opts.availableWidths = defaultWidths;
-        }
-
-        if (isArray(opts.availableWidths)) {
-            this.availableWidths = opts.availableWidths;
+        if (typeof this.availableWidths !== 'function'){
+          if (typeof this.availableWidths.length === 'number') {
             this.widthsMap = Imager.createWidthsMap(this.availableWidths);
-        }
-        else {
-            this.availableWidths = getKeys(opts.availableWidths);
-            this.widthsMap = opts.availableWidths;
-        }
+          }
+          else {
+            this.widthsMap = this.availableWidths;
+            this.availableWidths = getKeys(this.availableWidths);
+          }
 
-        this.availableWidths = this.availableWidths.sort(function (a, b) {
+          this.availableWidths = this.availableWidths.sort(function (a, b) {
             return a - b;
-        });
+          });
+        }
+
+
 
         if (elements) {
             this.divs = applyEach(elements, returnDirectValue);