brute force new keyed each block syntax

Author: Rich-Harris

src/parse/state/mustache.ts

@@ -274,7 +274,25 @@ export default function mustache(parser: Parser) {
 				parser.allowWhitespace();
 			}
 
-			if (parser.eat('@')) {
+			if (parser.eat('key')) {
+				parser.requireWhitespace();
+
+				const expression = readExpression(parser);
+
+				// TODO eventually, we should accept any expression, and turn
+				// it into a function. For now, assume that every expression
+				// follows the `foo.id` pattern, and equates to `@id`
+				if (
+					expression.type !== 'MemberExpression' ||
+					expression.property.computed ||
+					expression.property.type !== 'Identifier'
+				) {
+					parser.error('invalid key', expression.start);
+				}
+
+				block.key = expression.property.name;
+				parser.allowWhitespace();
+			} else if (parser.eat('@')) {
 				block.key = parser.readIdentifier();
 				if (!block.key) parser.error(`Expected name`);
 				parser.allowWhitespace();

test/parser/index.js

@@ -2,7 +2,7 @@ import assert from 'assert';
 import fs from 'fs';
 import { svelte, tryToLoadJson } from '../helpers.js';
 
-describe.only('parse', () => {
+describe('parse', () => {
 	fs.readdirSync('test/parser/samples').forEach(dir => {
 		if (dir[0] === '.') return;
 

test/parser/samples/each-block-keyed/_actual-v2.json

@@ -7,30 +7,38 @@
 		"children": [
 			{
 				"start": 0,
-				"end": 35,
-				"type": "Text",
-				"data": "{#each todos as todo key todo.id}\n\t"
-			},
-			{
-				"start": 35,
-				"end": 48,
-				"type": "Element",
-				"name": "p",
-				"attributes": [],
+				"end": 56,
+				"type": "EachBlock",
+				"expression": {
+					"type": "Identifier",
+					"start": 7,
+					"end": 12,
+					"name": "todos"
+				},
 				"children": [
 					{
-						"start": 38,
-						"end": 44,
-						"type": "Text",
-						"data": "{todo}"
+						"start": 35,
+						"end": 48,
+						"type": "Element",
+						"name": "p",
+						"attributes": [],
+						"children": [
+							{
+								"start": 38,
+								"end": 44,
+								"type": "MustacheTag",
+								"expression": {
+									"type": "Identifier",
+									"start": 39,
+									"end": 43,
+									"name": "todo"
+								}
+							}
+						]
 					}
-				]
-			},
-			{
-				"start": 48,
-				"end": 56,
-				"type": "Text",
-				"data": "\n{/each}"
+				],
+				"context": "todo",
+				"key": "id"
 			}
 		]
 	},

test/parser/samples/each-block-keyed/output-v2.json

@@ -1,36 +1,36 @@
 {
-	"hash": 2025411181,
+	"hash": "3sm0ec",
 	"html": {
 		"start": 0,
-		"end": 54,
+		"end": 56,
 		"type": "Fragment",
 		"children": [
 			{
 				"start": 0,
-				"end": 54,
+				"end": 56,
 				"type": "EachBlock",
 				"expression": {
 					"type": "Identifier",
-					"start": 8,
-					"end": 13,
+					"start": 7,
+					"end": 12,
 					"name": "todos"
 				},
 				"children": [
 					{
-						"start": 29,
-						"end": 44,
+						"start": 35,
+						"end": 48,
 						"type": "Element",
 						"name": "p",
 						"attributes": [],
 						"children": [
 							{
-								"start": 32,
-								"end": 40,
+								"start": 38,
+								"end": 44,
 								"type": "MustacheTag",
 								"expression": {
 									"type": "Identifier",
-									"start": 34,
-									"end": 38,
+									"start": 39,
+									"end": 43,
 									"name": "todo"
 								}
 							}

test/parser/samples/yield/input.html

@@ -1 +1 @@
-{{yield}}
+{{yield}}