parse each block index

compiler/parse/state/mustache.js

@@ -83,8 +83,16 @@ export default function mustache ( parser ) {
 			parser.requireWhitespace();
 
 			block.context = parser.read( validIdentifier ); // TODO check it's not a keyword
+			if ( !block.context ) parser.error( `Expected name` );
 
 			parser.allowWhitespace();
+
+			if ( parser.eat( ',' ) ) {
+				parser.allowWhitespace();
+				block.index = parser.read( validIdentifier );
+				if ( !block.index ) parser.error( `Expected name` );
+				parser.allowWhitespace();
+			}
 		}
 
 		parser.eat( '}}', true );

test/parser/each-block-indexed/input.svelte

@@ -0,0 +1,3 @@
+{{#each animals as animal, i}}
+	<p>{{i}}: {{animal}}</p>
+{{/each}}

test/parser/each-block-indexed/output.json

@@ -0,0 +1,63 @@
+{
+	"html": {
+		"start": 0,
+		"end": 66,
+		"type": "Fragment",
+		"children": [
+			{
+				"start": 0,
+				"end": 66,
+				"type": "EachBlock",
+				"expression": {
+					"start": 8,
+					"end": 15,
+					"type": "Identifier",
+					"name": "animals"
+				},
+				"context": "animal",
+				"index": "i",
+				"children": [
+					{
+						"start": 32,
+						"end": 56,
+						"type": "Element",
+						"name": "p",
+						"attributes": [],
+						"children": [
+							{
+								"start": 35,
+								"end": 40,
+								"type": "MustacheTag",
+								"expression": {
+									"start": 37,
+									"end": 38,
+									"type": "Identifier",
+									"name": "i"
+								}
+							},
+							{
+								"start": 40,
+								"end": 42,
+								"type": "Text",
+								"data": ": "
+							},
+							{
+								"start": 42,
+								"end": 52,
+								"type": "MustacheTag",
+								"expression": {
+									"start": 44,
+									"end": 50,
+									"type": "Identifier",
+									"name": "animal"
+								}
+							}
+						]
+					}
+				]
+			}
+		]
+	},
+	"css": null,
+	"js": null
+}

test/parser/each-block/input.svelte

@@ -1 +1,3 @@
-{{#each animals as animal}}<p>{{animal}}</p>{{/each}}
+{{#each animals as animal}}
+	<p>{{animal}}</p>
+{{/each}}

test/parser/each-block/output.json

@@ -1,12 +1,12 @@
 {
 	"html": {
 		"start": 0,
-		"end": 53,
+		"end": 56,
 		"type": "Fragment",
 		"children": [
 			{
 				"start": 0,
-				"end": 53,
+				"end": 56,
 				"type": "EachBlock",
 				"expression": {
 					"start": 8,
@@ -17,19 +17,19 @@
 				"context": "animal",
 				"children": [
 					{
-						"start": 27,
+						"start": 29,
-						"end": 44,
+						"end": 46,
 						"type": "Element",
 						"name": "p",
 						"attributes": [],
 						"children": [
 							{
-								"start": 30,
+								"start": 32,
-								"end": 40,
+								"end": 42,
 								"type": "MustacheTag",
 								"expression": {
-									"start": 32,
+									"start": 34,
-									"end": 38,
+									"end": 40,
 									"type": "Identifier",
 									"name": "animal"
 								}