From 9a43593a9e40b8cc7ef9cecf40b631dd26e01144 Mon Sep 17 00:00:00 2001
From: Rich-Harris <richard.a.harris@gmail.com>
Date: Sat, 6 May 2017 13:02:12 -0400
Subject: [PATCH] reintro unkeyed each block iterations as necessary

---
 src/generators/dom/visitors/EachBlock.js | 25 ++++++++++++++++--------
 src/shared/dom.js                        |  2 +-
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/src/generators/dom/visitors/EachBlock.js b/src/generators/dom/visitors/EachBlock.js
index dcf556ccfd..d30406598c 100644
--- a/src/generators/dom/visitors/EachBlock.js
+++ b/src/generators/dom/visitors/EachBlock.js
@@ -304,14 +304,23 @@ function unkeyed ( generator, block, state, node, snippet, { create_each_block,
 
 	if ( condition !== '' ) {
 		const forLoopBody = node._block.hasUpdateMethod ?
-			deindent`
-				if ( ${iterations}[${i}] ) {
-					${iterations}[${i}].update( changed, ${params}, ${each_block_value}, ${each_block_value}[${i}], ${i} );
-				} else {
-					${iterations}[${i}] = ${create_each_block}( ${params}, ${each_block_value}, ${each_block_value}[${i}], ${i}, ${block.component} );
-					${iterations}[${i}].${mountOrIntro}( ${parentNode}, ${anchor} );
-				}
-			` :
+			node._block.hasIntroMethod ?
+				deindent`
+					if ( ${iterations}[${i}] ) {
+						${iterations}[${i}].update( changed, ${params}, ${each_block_value}, ${each_block_value}[${i}], ${i} );
+					} else {
+						${iterations}[${i}] = ${create_each_block}( ${params}, ${each_block_value}, ${each_block_value}[${i}], ${i}, ${block.component} );
+					}
+					${iterations}[${i}].intro( ${parentNode}, ${anchor} );
+				` :
+				deindent`
+					if ( ${iterations}[${i}] ) {
+						${iterations}[${i}].update( changed, ${params}, ${each_block_value}, ${each_block_value}[${i}], ${i} );
+					} else {
+						${iterations}[${i}] = ${create_each_block}( ${params}, ${each_block_value}, ${each_block_value}[${i}], ${i}, ${block.component} );
+						${iterations}[${i}].mount( ${parentNode}, ${anchor} );
+					}
+				` :
 			deindent`
 				${iterations}[${i}] = ${create_each_block}( ${params}, ${each_block_value}, ${each_block_value}[${i}], ${i}, ${block.component} );
 				${iterations}[${i}].${mountOrIntro}( ${parentNode}, ${anchor} );
diff --git a/src/shared/dom.js b/src/shared/dom.js
index 6280783cb6..3c8bb78bc0 100644
--- a/src/shared/dom.js
+++ b/src/shared/dom.js
@@ -18,7 +18,7 @@ export function detachBetween ( before, after ) {
 
 export function destroyEach ( iterations, detach, start ) {
 	for ( var i = start; i < iterations.length; i += 1 ) {
-		iterations[i].destroy( detach );
+		if ( iterations[i] ) iterations[i].destroy( detach );
 	}
 }