From 0354a4e25138dd268dd3fad900a4666844379639 Mon Sep 17 00:00:00 2001
From: Leo Horie <lhorie@klick.com>
Date: Sun, 6 Jul 2014 22:36:49 -0400
Subject: [PATCH] fix diff when changing from element to empty array

---
 mithril.js             | 10 ++++------
 tests/mithril-tests.js |  7 +++++++
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/mithril.js b/mithril.js
index a77af48f..0c063d2b 100644
--- a/mithril.js
+++ b/mithril.js
@@ -104,18 +104,16 @@ Mithril = m = new function app(window) {
 				var item = build(parentElement, parentTag, cached, index, data[i], cached[cacheCount], shouldReattach, index + subArrayCount || subArrayCount, editable, namespace, configs)
 				if (item === undefined) continue
 				if (!item.nodes.intact) intact = false
-				subArrayCount += item instanceof Array ? item.length : 1
+				var isArray = item instanceof Array
+				subArrayCount += isArray ? item.length : 1
 				cached[cacheCount++] = item
 			}
 			if (!intact) {
 				for (var i = 0; i < data.length; i++) {
 					if (cached[i] !== undefined) nodes = nodes.concat(cached[i].nodes)
 				}
-				for (var i = nodes.length, node; node = cached.nodes[i]; i++) {
-					if (node.parentNode !== null && node.parentNode.childNodes.length != nodes.length) {
-						node.parentNode.removeChild(node)
-						if (cached[i]) unload(cached[i])
-					}
+				for (var i = 0, node; node = cached.nodes[i]; i++) {
+					if (node.parentNode !== null && nodes.indexOf(node) < 0) node.parentNode.removeChild(node)
 				}
 				for (var i = cached.nodes.length, node; node = nodes[i]; i++) {
 					if (node.parentNode === null) parentElement.appendChild(node)
diff --git a/tests/mithril-tests.js b/tests/mithril-tests.js
index 1e0efded..c2b00dad 100644
--- a/tests/mithril-tests.js
+++ b/tests/mithril-tests.js
@@ -660,6 +660,13 @@ function testMithril(mock) {
 		m.render(root, m("main", {config: configParent}, m("b", {config: configChild})))
 		return unloadedParent === 1 && unloadedChild === 1
 	})
+	test(function() {
+		//https://github.com/lhorie/mithril.js/issues/150
+		var root = mock.document.createElement("div")
+		m.render(root, [m("a"), m("div")])
+		m.render(root, [[], m("div")])
+		return root.childNodes.length == 1 && root.childNodes[0].nodeName == "DIV"
+	})
 	//end m.render
 
 	//m.redraw