From d44176c888d6b76fab7c7017632c505799a84b99 Mon Sep 17 00:00:00 2001
From: Leo Horie <lhorie@klick.com>
Date: Tue, 1 Jul 2014 22:26:12 -0400
Subject: [PATCH] re-render from scratch on route changes

---
 docs/change-log.md     |  4 +++
 mithril.js             | 18 ++++++++---
 tests/mithril-tests.js | 70 ++++++++++++++++--------------------------
 3 files changed, 44 insertions(+), 48 deletions(-)

diff --git a/docs/change-log.md b/docs/change-log.md
index c8d4c343..454e2b8b 100644
--- a/docs/change-log.md
+++ b/docs/change-log.md
@@ -5,12 +5,16 @@
 ### News:
 
 -	config contexts can now have an `onunload` property for clean up tasks after elements are detached from the document
+-	route changes now re-render from scratch, rather than attempting a virtual dom diff
+-	virtual elements that are children of an array can now accept a `key` attribute which maintains the identity of the underlying DOM elements when the array gets shuffled [#98](https://github.com/lhorie/mithril.js/issues/98)
 
 ### Bug Fixes:
 
 -	fixed a subtree directive bug that happened in inputs inside loops
 -	fixed select.value so that the correct option is displayed on first render
 -	in m.request, non-idempotent methods now automatically send appropriate Content-Type header if `serialize` is `JSON.stringify` [#139](https://github.com/lhorie/mithril.js/issues/139)
+-	`m` selectors now correctly handle empty attribute values like `[href='']`
+-	pre-existing nodes in a root element now get cleared if there's no cell cache associated with the element [#60](https://github.com/lhorie/mithril.js/issues/60)
 
 ---
 
diff --git a/mithril.js b/mithril.js
index dd16550b..bb74230e 100644
--- a/mithril.js
+++ b/mithril.js
@@ -297,12 +297,16 @@ Mithril = m = new function app(window) {
 	m.render = function(root, cell) {
 		var configs = []
 		if (!root) throw new Error("Please ensure the DOM element exists before rendering a template into it.")
-		var index = nodeCache.indexOf(root)
-		var id = index < 0 ? nodeCache.push(root) - 1 : index
+		var id = getCellCacheId(root)
 		var node = root == window.document || root == window.document.documentElement ? documentNode : root
+		if (cellCache[id] === undefined) clear(node.childNodes)
 		cellCache[id] = build(node, null, undefined, undefined, cell, cellCache[id], false, 0, null, undefined, configs)
 		for (var i = 0; i < configs.length; i++) configs[i]()
 	}
+	function getCellCacheId(element) {
+		var index = nodeCache.indexOf(element)
+		return index < 0 ? nodeCache.push(element) - 1 : index
+	}
 
 	m.trust = function(value) {
 		value = new String(value)
@@ -428,17 +432,23 @@ Mithril = m = new function app(window) {
 		}
 
 		for (var route in router) {
-			if (route == path) return !void m.module(root, router[route])
+			if (route == path) {
+				clear(root.childNodes, cellCache[getCellCacheId(root)])
+				m.module(root, router[route])
+				return true
+			}
 
 			var matcher = new RegExp("^" + route.replace(/:[^\/]+?\.{3}/g, "(.*?)").replace(/:[^\/]+/g, "([^\\/]+)") + "\/?$")
 
 			if (matcher.test(path)) {
-				return !void path.replace(matcher, function() {
+				clear(root.childNodes, cellCache[getCellCacheId(root)])
+				path.replace(matcher, function() {
 					var keys = route.match(/:[^\/]+/g) || []
 					var values = [].slice.call(arguments, 1, -2)
 					for (var i = 0; i < keys.length; i++) routeParams[keys[i].replace(/:|\./g, "")] = decodeSpace(values[i])
 					m.module(root, router[route])
 				})
+				return true
 			}
 		}
 	}
diff --git a/tests/mithril-tests.js b/tests/mithril-tests.js
index 9568e988..c71f75b6 100644
--- a/tests/mithril-tests.js
+++ b/tests/mithril-tests.js
@@ -577,6 +577,32 @@ function testMithril(mock) {
 		m.render(root, m("textarea", ["test1"]))
 		return root.childNodes[0].value === "test1"
 	})
+	test(function() {
+		var root = mock.document.createElement("div")
+		var unloaded = 0
+		m.render(root, [
+			m("div", {
+				key: 1,
+				config: function(el, init, ctx) {
+					ctx.onunload = function() {
+						unloaded++
+					}
+				}
+			})
+		])
+		m.render(root, [
+			m("div", {key: 2}),
+			m("div", {
+				key: 1,
+				config: function(el, init, ctx) {
+					ctx.onunload = function() {
+						unloaded++
+					}
+				}
+			})
+		])
+		return unloaded == 0
+	})
 	//end m.render
 
 	//m.redraw
@@ -1028,50 +1054,6 @@ function testMithril(mock) {
 		mock.performance.$elapse(50) //setup
 		mock.location.search = "?"
 
-		var root = mock.document.createElement("div")
-		var unloaded = 0
-		m.route.mode = "search"
-		m.route(root, "/", {
-			"/": {
-				controller: function() {},
-				view: function() {
-					return [
-						m("div", {
-							key: 1,
-							config: function(el, init, ctx) {
-								ctx.onunload = function() {
-									unloaded++
-								}
-							}
-						})
-					]
-				}
-			},
-			"/test19": {
-				controller: function() {},
-				view: function() {
-					return [
-						m("div", {
-							key: 1,
-							config: function(el, init, ctx) {
-								ctx.onunload = function() {
-									unloaded++
-								}
-							}
-						})
-					]
-				}
-			}
-		})
-		mock.performance.$elapse(50)
-		m.route("/test19")
-		mock.performance.$elapse(50) //teardown
-		return unloaded == 0
-	})
-	test(function() {
-		mock.performance.$elapse(50) //setup
-		mock.location.search = "?"
-
 		var root = mock.document.createElement("div")
 		var unloaded = 0
 		m.route.mode = "search"