From 6c6e712ee105474f888a9df80215bb118e15c265 Mon Sep 17 00:00:00 2001
From: Daniel Hug <daniel@hugwebdesign.com>
Date: Fri, 31 Mar 2017 15:40:58 -0700
Subject: [PATCH] live event listening

---
 panels.js | 114 +++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 82 insertions(+), 32 deletions(-)

diff --git a/panels.js b/panels.js
index ebfea85..5fd9ca5 100644
--- a/panels.js
+++ b/panels.js
@@ -1,5 +1,38 @@
 // toggleable tabbed panels
 (function(){
+	// get nearest parent element matching selector
+	var closestParent = (function() {
+		var el = HTMLElement.prototype;
+		var matches = el.matches || el.webkitMatchesSelector || el.mozMatchesSelector || el.msMatchesSelector;
+
+		function closestParent(el, selector) {
+			if (el === null) return null;
+			if (matches.call(el, selector)) {
+				return el;
+			} else {
+				return closestParent(el.parentElement, selector);
+			}
+		}
+		return closestParent;
+	})();
+
+
+	// handle events whose target matches a selector
+	// works even on elements created after the event listener was added:
+	//
+	// delegateEvent('.todo .remove', 'click', function(removeBtn) {
+	//     removeTodo(removeBtn.parentNode);
+	// });
+
+	function delegateEvent(selector, eventType, handler, elementScope) {
+		(elementScope || document).addEventListener(eventType, function(event) {
+			var listeningTarget = closestParent(event.target, selector);
+			if (listeningTarget) {
+				handler.call(listeningTarget, event);
+			}
+		});
+	}
+
 	// Get descendants of scopeEl with className that have no
 	// .tabbed-panels ancestor which is also a descendant of scopeEl
 	// This is needed to support nesting of tabbed panels.
@@ -14,48 +47,65 @@
 		});
 	}
 
-	[].forEach.call(document.getElementsByClassName('tabbed-panels'), function(parent) {
+	function isAInB(a, b) {
+		return a === b || b.contains(a);
+	}
+
+	function tabClick(clickedTab) {
+		clickedTab = clickedTab.parentNode ? clickedTab : this;
+		var parent = closestParent(clickedTab, '.tabbed-panels');
+		if (!parent) return;
+
 		var tabs = getElements('tab', parent);
 		var panels = getElements('panel', parent);
 		var closeable = parent.classList.contains('closeable');
-		var hovering = parent.classList.contains('hovering');
-		var lastClickedTab = null;
-		var lastClickedTabI = null;
+		var clickedTabI = tabs.indexOf(clickedTab);
 
-		function tabClick(clickedTab, clickedTabI) {
-			// non-clicked tabs: deactivate
-			tabs.forEach(function(tab) {
-				if (tab != clickedTab) tab.classList.remove('active');
-			});
+		// non-clicked tabs: deactivate
+		tabs.forEach(function(tab) {
+			if (tab != clickedTab) tab.classList.remove('active');
+		});
 
-			// clicked tab: if closeable, toggle its active state, otherwise activate
-			var isActive = clickedTab.classList[closeable ? 'toggle' : 'add']('active');
+		// clicked tab: if closeable, toggle its active state, otherwise activate
+		var isActive = clickedTab.classList[closeable ? 'toggle' : 'add']('active');
 
-			// parent: if not closeable or if a tab is active, activate parent, otherwise deactivate
-			parent.classList[(!closeable || isActive) ? 'add' : 'remove']('active');
+		// parent: if not closeable or if a tab is active, activate parent, otherwise deactivate
+		parent.classList[(!closeable || isActive) ? 'add' : 'remove']('active');
 
-			// panels: activate clicked tab's panel, deactivate other panels
-			panels.forEach(function(panel, panelI) {
-				panel.classList[panelI === clickedTabI ? (closeable ? 'toggle' : 'add') : 'remove']('active');
-			});
+		// panels: activate clicked tab's panel, deactivate other panels
+		panels.forEach(function(panel, panelI) {
+			if (panelI === clickedTabI) {
+				panel.classList[closeable ? 'toggle' : 'add']('active');
+			} else {
+				panel.classList.remove('active');
+			}
+		});
+	}
 
-			lastClickedTab = clickedTab;
-			lastClickedTabI = clickedTabI;
-		}
+	delegateEvent('.tab', 'click', tabClick);
 
-		tabs.forEach(function(tab, i) {
-			tab.addEventListener('click', tabClick.bind(null, tab, i));
-		});
+	window.addEventListener('click', function(event) {
+		var parents = [].slice.call(document.querySelectorAll('.tabbed-panels.hovering.closeable.active'));
+		parents.forEach(function(parent) {
+			var tabs = getElements('tab', parent);
+			var panels = getElements('panel', parent);
+
+			// exit if click was in a tab or panel
+			if (tabs.some(function(tab) {
+				return isAInB(event.target, tab);
+			}) || panels.some(function(panel) {
+				return isAInB(event.target, panel);
+			})) return;
 
-		if (closeable && hovering) {
-			window.addEventListener('click', function(e) {
-				if (
-					parent.classList.contains('active') &&
-					(!parent.contains(e.target) || e.target === parent)
-				) {
-					tabClick(lastClickedTab, lastClickedTabI);
+			// otherwise unactivate everything
+			for (var i = 0; i < tabs.length; i++) {
+				if (tabs[i].classList.contains('active')) {
+					parent.classList.remove('active');
+					tabs[i].classList.remove('active');
+					panels[i].classList.remove('active');
+					return;
 				}
-			});
-		}
+			}
+		});
 	});
 })();
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