From fec55a1ccd0f1142b4d1268c53e45ea00c27918c Mon Sep 17 00:00:00 2001
From: Arpad Borsos <arpad.borsos@googlemail.com>
Date: Mon, 5 Dec 2016 09:29:44 +0100
Subject: [PATCH 1/2] add each-else support to parser

---
 compiler/parse/state/mustache.js        |  4 +-
 test/parser/each-block-else/input.html  |  5 ++
 test/parser/each-block-else/output.json | 67 +++++++++++++++++++++++++
 3 files changed, 75 insertions(+), 1 deletion(-)
 create mode 100644 test/parser/each-block-else/input.html
 create mode 100644 test/parser/each-block-else/output.json

diff --git a/compiler/parse/state/mustache.js b/compiler/parse/state/mustache.js
index b27e694608..98d371b418 100644
--- a/compiler/parse/state/mustache.js
+++ b/compiler/parse/state/mustache.js
@@ -112,7 +112,9 @@ export default function mustache ( parser ) {
 
 	else if ( parser.eat( 'else' ) ) {
 		const block = parser.current();
-		if ( block.type !== 'IfBlock' ) parser.error( 'Cannot have an {{else}} block outside an {{#if ...}} block' );
+		if ( block.type !== 'IfBlock' && block.type !== 'EachBlock' ) {
+			parser.error( 'Cannot have an {{else}} block outside an {{#if ...}} or {{#each ...}} block' );
+		}
 
 		parser.allowWhitespace();
 		parser.eat( '}}', true );
diff --git a/test/parser/each-block-else/input.html b/test/parser/each-block-else/input.html
new file mode 100644
index 0000000000..59925e8db7
--- /dev/null
+++ b/test/parser/each-block-else/input.html
@@ -0,0 +1,5 @@
+{{#each animals as animal}}
+	<p>{{animal}}</p>
+{{else}}
+	<p>no animals</p>
+{{/each}}
diff --git a/test/parser/each-block-else/output.json b/test/parser/each-block-else/output.json
new file mode 100644
index 0000000000..8d82d5a677
--- /dev/null
+++ b/test/parser/each-block-else/output.json
@@ -0,0 +1,67 @@
+{
+	"html": {
+		"start": 0,
+		"end": 84,
+		"type": "Fragment",
+		"children": [
+			{
+				"start": 0,
+				"end": 84,
+				"type": "EachBlock",
+				"expression": {
+					"start": 8,
+					"end": 15,
+					"type": "Identifier",
+					"name": "animals"
+				},
+				"context": "animal",
+				"children": [
+					{
+						"start": 29,
+						"end": 46,
+						"type": "Element",
+						"name": "p",
+						"attributes": [],
+						"children": [
+							{
+								"start": 32,
+								"end": 42,
+								"type": "MustacheTag",
+								"expression": {
+									"start": 34,
+									"end": 40,
+									"type": "Identifier",
+									"name": "animal"
+								}
+							}
+						]
+					}
+				],
+				"else": {
+					"children": [
+						{
+							"attributes": [],
+							"children": [
+								{
+									"data": "no animals",
+									"end": 70,
+									"start": 60,
+									"type": "Text"
+								}
+							],
+							"end": 74,
+							"name": "p",
+							"start": 57,
+							"type": "Element"
+						}
+					],
+					"end": 75,
+					"start": 55,
+					"type": "ElseBlock"
+				}
+			}
+		]
+	},
+	"css": null,
+	"js": null
+}

From 5d256eb600d152baac0c5f4f1b8a2fec68d0a840 Mon Sep 17 00:00:00 2001
From: Arpad Borsos <arpad.borsos@googlemail.com>
Date: Mon, 5 Dec 2016 09:58:39 +0100
Subject: [PATCH 2/2] add support for each-else in codegen

---
 compiler/generate/visitors/EachBlock.js  | 68 ++++++++++++++++++++++--
 test/compiler/each-block-else/_config.js | 17 ++++++
 test/compiler/each-block-else/main.html  |  7 +++
 3 files changed, 87 insertions(+), 5 deletions(-)
 create mode 100644 test/compiler/each-block-else/_config.js
 create mode 100644 test/compiler/each-block-else/main.html

diff --git a/compiler/generate/visitors/EachBlock.js b/compiler/generate/visitors/EachBlock.js
index 089ab59876..845105160f 100644
--- a/compiler/generate/visitors/EachBlock.js
+++ b/compiler/generate/visitors/EachBlock.js
@@ -5,8 +5,11 @@ export default {
 	enter ( generator, node ) {
 		const i = generator.counters.each++;
 		const name = `eachBlock_${i}`;
+		const elseName = `${name}_else`;
 		const iterations = `${name}_iterations`;
 		const renderer = `renderEachBlock_${i}`;
+		const renderElse = `${renderer}_else`;
+		const { params } = generator.current;
 
 		const listName = `${name}_value`;
 
@@ -21,12 +24,21 @@ export default {
 		generator.current.initStatements.push( deindent`
 			var ${name}_value = ${snippet};
 			var ${iterations} = [];
+			${node.else ? `var ${elseName} = null;` : ''}
 
 			for ( var i = 0; i < ${name}_value.length; i += 1 ) {
-				${iterations}[i] = ${renderer}( ${generator.current.params}, ${listName}, ${listName}[i], i, component );
+				${iterations}[i] = ${renderer}( ${params}, ${listName}, ${listName}[i], i, component );
 				${!isToplevel ? `${iterations}[i].mount( ${anchor}.parentNode, ${anchor} );` : ''}
 			}
 		` );
+		if ( node.else ) {
+			generator.current.initStatements.push( deindent`
+				if ( !${name}_value.length ) {
+					${elseName} = ${renderElse}( ${params}, component );
+					${!isToplevel ? `${elseName}.mount( ${anchor}.parentNode, ${anchor} );` : ''}
+				}
+			` );
+		}
 
 		if ( isToplevel ) {
 			generator.current.mountStatements.push( deindent`
@@ -34,6 +46,13 @@ export default {
 					${iterations}[i].mount( ${anchor}.parentNode, ${anchor} );
 				}
 			` );
+			if ( node.else ) {
+				generator.current.mountStatements.push( deindent`
+					if ( ${elseName} ) {
+						${elseName}.mount( ${anchor}.parentNode, ${anchor} );
+					}
+				` );
+			}
 		}
 
 		generator.current.updateStatements.push( deindent`
@@ -41,10 +60,10 @@ export default {
 
 			for ( var i = 0; i < ${name}_value.length; i += 1 ) {
 				if ( !${iterations}[i] ) {
-					${iterations}[i] = ${renderer}( ${generator.current.params}, ${listName}, ${listName}[i], i, component );
+					${iterations}[i] = ${renderer}( ${params}, ${listName}, ${listName}[i], i, component );
 					${iterations}[i].mount( ${anchor}.parentNode, ${anchor} );
 				} else {
-					${iterations}[i].update( changed, ${generator.current.params}, ${listName}, ${listName}[i], i );
+					${iterations}[i].update( changed, ${params}, ${listName}, ${listName}[i], i );
 				}
 			}
 
@@ -54,12 +73,51 @@ export default {
 
 			${iterations}.length = ${listName}.length;
 		` );
+		if ( node.else ) {
+			generator.current.updateStatements.push( deindent`
+				if ( !${name}_value.length && ${elseName} ) {
+					${elseName}.update( changed, ${params} );
+				} else if ( !${name}_value.length ) {
+					${elseName} = ${renderElse}( ${params}, component );
+					${elseName}.mount( ${anchor}.parentNode, ${anchor} );
+				} else if ( ${elseName} ) {
+					${elseName}.teardown( true );
+				}
+			` );
+		}
 
 		generator.current.teardownStatements.push( deindent`
 			for ( var i = 0; i < ${iterations}.length; i += 1 ) {
 				${iterations}[i].teardown( ${isToplevel ? 'detach' : 'false'} );
 			}
 		` );
+		if ( node.else ) {
+			generator.current.teardownStatements.push( deindent`
+				if ( ${elseName} ) {
+					${elseName}.teardown( ${isToplevel ? 'detach' : 'false'} );
+				}
+			` );
+		}
+
+		if ( node.else ) {
+			generator.push({
+				useAnchor: false,
+				name: renderElse,
+				target: 'target',
+				localElementDepth: 0,
+
+				initStatements: [],
+				mountStatements: [],
+				updateStatements: [],
+				detachStatements: [],
+				teardownStatements: [],
+
+				counter: counter()
+			});
+			node.else.children.forEach( generator.visit );
+			generator.addRenderer( generator.current );
+			generator.pop();
+		}
 
 		const indexNames = Object.assign( {}, generator.current.indexNames );
 		const indexName = indexNames[ node.context ] = ( node.index || `${node.context}__index` );
@@ -76,7 +134,7 @@ export default {
 		const contextDependencies = Object.assign( {}, generator.current.contextDependencies );
 		contextDependencies[ node.context ] = dependencies;
 
-		const params = generator.current.params + `, ${listName}, ${node.context}, ${indexName}`;
+		const blockParams = generator.current.params + `, ${listName}, ${node.context}, ${indexName}`;
 
 		generator.push({
 			useAnchor: false,
@@ -92,7 +150,7 @@ export default {
 
 			indexNames,
 			listNames,
-			params,
+			params: blockParams,
 
 			initStatements: [],
 			mountStatements: [],
diff --git a/test/compiler/each-block-else/_config.js b/test/compiler/each-block-else/_config.js
new file mode 100644
index 0000000000..313b7fa7e3
--- /dev/null
+++ b/test/compiler/each-block-else/_config.js
@@ -0,0 +1,17 @@
+export default {
+	data: {
+		animals: [ 'alpaca', 'baboon', 'capybara' ],
+		foo: 'something else'
+	},
+	html: 'before\n<p>alpaca</p><p>baboon</p><p>capybara</p>\nafter',
+	test ( assert, component, target ) {
+		component.set({ animals: [] });
+		assert.htmlEqual( target.innerHTML, 'before\n<p>no animals, but rather something else</p>\nafter' );
+
+		component.set({ foo: 'something other' });
+		assert.htmlEqual( target.innerHTML, 'before\n<p>no animals, but rather something other</p>\nafter' );
+		
+		component.set({ animals: ['wombat'] });
+		assert.htmlEqual( target.innerHTML, 'before\n<p>wombat</p>\nafter' );
+	}
+};
diff --git a/test/compiler/each-block-else/main.html b/test/compiler/each-block-else/main.html
new file mode 100644
index 0000000000..6c13e5fb23
--- /dev/null
+++ b/test/compiler/each-block-else/main.html
@@ -0,0 +1,7 @@
+before
+{{#each animals as animal}}
+	<p>{{animal}}</p>
+{{else}}
+	<p>no animals, but rather {{foo}}</p>
+{{/each}}
+after