From 53e7c4ee56725897a3159e28621735aca4d7206d Mon Sep 17 00:00:00 2001
From: Tom Spencer <fiznool@gmail.com>
Date: Wed, 2 Dec 2015 19:43:31 +0000
Subject: [PATCH 1/2] Added a cleanup method to Imager prototype

---
 Imager.js | 53 +++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 47 insertions(+), 6 deletions(-)

diff --git a/Imager.js b/Imager.js
index 19d3c1b..a1ed4d5 100644
--- a/Imager.js
+++ b/Imager.js
@@ -14,6 +14,19 @@
         }
     })();
 
+    var removeEvent = (function () {
+      if (document.removeEventListener) {
+            return function removeStandardEventListener(el, eventName, fn) {
+                return el.removeEventListener(eventName, fn, false);
+            };
+        }
+        else {
+            return function removeIEEventListener(el, eventName, fn) {
+                return el.detachEvent('on' + eventName, fn);
+            };
+        }
+    })();
+
     var defaultWidths = [96, 130, 165, 200, 235, 270, 304, 340, 375, 410, 445, 485, 520, 555, 590, 625, 660, 695, 736];
 
     var getKeys = typeof Object.keys === 'function' ? Object.keys : function (object) {
@@ -144,6 +157,8 @@
         }
 
         this.divs = [];
+        this.scrollListeners = [];
+        this.resizeListeners = [];
         this.add(elements || this.selector);
         this.ready(opts.onReady);
 
@@ -424,9 +439,12 @@
     Imager.prototype.registerResizeEvent = function (filterFn) {
         var self = this;
 
-        addEvent(window, 'resize', debounce(function () {
+        var resizeListener = debounce(function () {
             self.checkImagesNeedReplacing(self.divs, filterFn);
-        }, 100));
+        }, 100);
+
+        addEvent(window, 'resize', resizeListener);
+        this.resizeListeners.push(resizeListener);
     };
 
     Imager.prototype.registerScrollEvent = function () {
@@ -438,14 +456,37 @@
             self.scrollCheck();
         }, self.scrollDelay);
 
-        addEvent(window, 'scroll', function () {
+        var onScroll = function () {
             self.scrolled = true;
-        });
+        };
 
-        addEvent(window, 'resize', function () {
+        var onResize = function () {
             self.viewportHeight = document.documentElement.clientHeight;
             self.scrolled = true;
-        });
+        };
+
+        addEvent(window, 'scroll', onScroll);
+        addEvent(window, 'resize', onResize);
+
+        this.scrollListeners.push(onScroll);
+        this.resizeListeners.push(onResize);
+    };
+
+    Imager.prototype.cleanup = function () {
+      applyEach(this.resizeListeners, function(listener) {
+        removeEvent(window, 'resize', listener);
+      });
+      applyEach(this.scrollListeners, function(listener) {
+        removeEvent(window, 'scroll', listener);
+      });
+
+      if(this.interval) {
+        window.clearInterval(this.interval);
+      }
+
+      this.resizeListeners = [];
+      this.scrollListeners = [];
+      this.interval = null;
     };
 
     Imager.getPageOffsetGenerator = function getPageVerticalOffset(testCase) {

From 1749b4f2a71380d531f7c0a820c19b28c61f9ced Mon Sep 17 00:00:00 2001
From: Tom Spencer <fiznool@gmail.com>
Date: Tue, 12 Jan 2016 17:13:37 +0000
Subject: [PATCH 2/2] Add tests for cleanup method

---
 test/fixtures/cleanup.html |  4 +++
 test/unit/core.js          | 68 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 test/fixtures/cleanup.html

diff --git a/test/fixtures/cleanup.html b/test/fixtures/cleanup.html
new file mode 100644
index 0000000..cf5eb18
--- /dev/null
+++ b/test/fixtures/cleanup.html
@@ -0,0 +1,4 @@
+<div class="delayed-image-load" data-src="base/test/fixtures/media/A-320.jpg"></div>
+<div class="delayed-image-load" data-src="base/test/fixtures/media/B-320.jpg"></div>
+<div class="delayed-image-load" data-src="base/test/fixtures/media/B-640.jpg"></div>
+<div class="delayed-image-load" data-src="base/test/fixtures/media/C-320.jpg"></div>
diff --git a/test/unit/core.js b/test/unit/core.js
index deaf5e9..317843c 100644
--- a/test/unit/core.js
+++ b/test/unit/core.js
@@ -231,6 +231,74 @@ describe('Imager.js', function () {
         });
     });
 
+    describe('cleanup', function() {
+        var removeEvtStub, getExpectedEvtName;
+
+        beforeEach(function() {
+            if(document.removeEventListener) {
+                removeEvtStub = sandbox.stub(window, 'removeEventListener');
+                getExpectedEvtName = function(name) {
+                    return name;
+                };
+
+            } else {
+                removeEvtStub = sandbox.stub(window, 'detachEvent');
+                getExpectedEvtName = function(name) {
+                    return 'on' + name;
+                };
+            }
+        });
+
+        it('should cleanup after using onResize option', function(done) {
+            fixtures = loadFixtures('cleanup');
+            var imgr = new Imager({
+                onResize: true
+            });
+            imgr.ready(function () {
+                expect(imgr.resizeListeners.length).to.be(1);
+                expect(imgr.scrollListeners.length).to.be(0);
+
+                imgr.cleanup();
+
+                expect(imgr.resizeListeners.length).to.be(0);
+                expect(imgr.scrollListeners.length).to.be(0);
+
+                expect(removeEvtStub.called).to.be(true);
+                expect(removeEvtStub.callCount).to.be(1);
+                expect(removeEvtStub.firstCall.args[0]).to.be(getExpectedEvtName('resize'));
+                done();
+            });
+        });
+
+        it('should cleanup after using lazyload option', function(done) {
+            sandbox.stub(window, 'clearInterval');
+            fixtures = loadFixtures('cleanup');
+            var imgr = new Imager({
+                lazyload: true
+            });
+            imgr.ready(function () {
+                expect(imgr.resizeListeners.length).to.be(2);
+                expect(imgr.scrollListeners.length).to.be(1);
+                expect(imgr.interval).to.be.defined;
+
+                imgr.cleanup();
+
+                expect(imgr.resizeListeners.length).to.be(0);
+                expect(imgr.scrollListeners.length).to.be(0);
+                expect(imgr.interval).to.be.null;
+
+                expect(removeEvtStub.called).to.be(true);
+                expect(removeEvtStub.callCount).to.be(3);
+                expect(removeEvtStub.firstCall.args[0]).to.be(getExpectedEvtName('resize'));
+                expect(removeEvtStub.secondCall.args[0]).to.be(getExpectedEvtName('resize'));
+                expect(removeEvtStub.thirdCall.args[0]).to.be(getExpectedEvtName('scroll'));
+                expect(window.clearInterval.called).to.be(true);
+
+                done();
+            });
+        });
+    });
+
     describe('isThisElementOnScreen', function(){
         var offsetStub, imgr;