From ee7c5d688b32959671400eaf24e6eab1f6927bd4 Mon Sep 17 00:00:00 2001
From: Mimu <brice.bernard1@gmail.com>
Date: Mon, 2 Mar 2015 23:49:03 +0100
Subject: [PATCH] Add directive before editing

---
 disableWhenHidden.js | 128 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 128 insertions(+)
 create mode 100755 disableWhenHidden.js

diff --git a/disableWhenHidden.js b/disableWhenHidden.js
new file mode 100755
index 0000000..a2561ca
--- /dev/null
+++ b/disableWhenHidden.js
@@ -0,0 +1,128 @@
+/**
+ * Created by Brice on 01/10/2014.
+ */
+
+
+/**
+ * Listen to the scroll event and broadcast an event to disable / enable the watchers of the "dwhElements"
+ */
+webassadorsApp.directive('disableWhenHidden', ['$timeout', '$compile', 'CommonTools', function ($timeout, $compile, CommonTools) {
+    'use strict';
+    return {
+        restrict: 'A',
+        link: function (scope) {
+            var checkElements = CommonTools.debounce(function () {
+                scope.$broadcast('dwhCheckElements');
+            }, 250);
+            // Hide / Show posts every time the user scrolls
+            document.addEventListener('scroll', checkElements);
+        }
+    };
+}]);
+
+/**
+ * When out of sight, we empty the watchers, when back up we bring them back !
+ */
+webassadorsApp.directive('dwhElement', function () {
+    'use strict';
+    return {
+        restrict: 'A',
+        link: function (scope, element) {
+            var el = element[0];
+            var m = 1000; // Range of "errors" outside the viewport
+            var wArray; // Array to store all the watchers
+            var isHidden = false; // Used to prevent useless computation
+
+            /**
+             * Store all the watchers and empty it so we never go crazy
+             */
+            var disableWatchers = function () {
+                // Hide element
+                wArray = [];
+                leaveHimToDie(el);
+                isHidden = true;
+            };
+
+            /**
+             * Bring the watchers back
+             */
+            var enableWatchers = function () {
+                bringHimBack(el);
+                isHidden = false;
+            };
+
+            // Listen to scroll events
+            scope.$on('dwhCheckElements', function () {
+                var coordinates = el.getBoundingClientRect();
+                if (coordinates.bottom > 0 - m && coordinates.top < window.innerHeight + m) {
+                    if (isHidden) {
+                        enableWatchers();
+                    }
+                } else if (!isHidden) {
+                    disableWatchers();
+                }
+            });
+
+            /**
+             * Goes through every child elements and store the watchers if they exist
+             * Then empty every array to remove them
+             * @param elem
+             */
+            var leaveHimToDie = function (elem) {
+                elem = angular.element(elem);
+                var i = 0;
+
+                function getElemWatchers(element) {
+                    wArray[i] = [];
+                    wArray[i][0] = getWatchersFromScope(element.data().$isolateScope);
+                    wArray[i][1] = getWatchersFromScope(element.data().$scope);
+
+                    angular.forEach(element.children(), function (childElement) {
+                        i++;
+                        getElemWatchers(angular.element(childElement));
+                    });
+                }
+
+                function getWatchersFromScope(scope) {
+                    if (scope) {
+                        var tmp = scope.$$watchers || [];
+                        scope.$$watchers = [];
+                        return tmp;
+                    } else {
+                        return [];
+                    }
+                }
+
+                getElemWatchers(elem);
+            };
+
+            /**
+             * Go through every child elements and restore the watchers from the array we stored with "leaveHimToDie"
+             * @param elem
+             */
+            var bringHimBack = function (elem) {
+                elem = angular.element(elem);
+                var i = 0;
+
+                function setElemWatchers(element) {
+                    setWatchersFromScope(element.data().$isolateScope, 0);
+                    setWatchersFromScope(element.data().$scope, 1);
+
+                    angular.forEach(element.children(), function (childElement) {
+                        i++;
+                        setElemWatchers(angular.element(childElement));
+                    });
+                }
+
+                function setWatchersFromScope(scope, n) {
+                    if (scope) {
+                        scope.$$watchers = wArray[i][n];
+                    }
+                }
+
+                // Start the loop
+                setElemWatchers(elem);
+            };
+        }
+    };
+});
\ No newline at end of file