destructuring

src/compile/nodes/EachBlock.ts

@@ -6,6 +6,7 @@ import createDebuggingComment from '../../utils/createDebuggingComment';
 import Expression from './shared/Expression';
 import mapChildren from './shared/mapChildren';
 import TemplateScope from './shared/TemplateScope';
+import unpackDestructuring from '../../utils/unpackDestructuring';
 
 export default class EachBlock extends Node {
 	type: 'EachBlock';
@@ -18,7 +19,7 @@ export default class EachBlock extends Node {
 	context: string;
 	key: Expression;
 	scope: TemplateScope;
-	destructuredContexts: string[];
+	contexts: Array<{ name: string, tail: string }>;
 
 	children: Node[];
 	else?: ElseBlock;
@@ -27,7 +28,7 @@ export default class EachBlock extends Node {
 		super(compiler, parent, scope, info);
 
 		this.expression = new Expression(compiler, this, scope, info.expression);
-		this.context = info.context;
+		this.context = info.context.name || 'each'; // TODO this is used to facilitate binding; currently fails with destructuring
 		this.index = info.index;
 
 		this.key = info.key
@@ -36,7 +37,12 @@ export default class EachBlock extends Node {
 
 		this.scope = scope.child();
 
-		this.scope.add(this.context, this.expression.dependencies);
+		this.contexts = [];
+		unpackDestructuring(this.contexts, info.context, '');
+
+		this.contexts.forEach(context => {
+			this.scope.add(context.key.name, this.expression.dependencies);
+		});
 
 		if (this.index) {
 			// index can only change if this is a keyed each block
@@ -44,12 +50,6 @@ export default class EachBlock extends Node {
 			this.scope.add(this.index, dependencies);
 		}
 
-		// TODO more general approach to destructuring
-		this.destructuredContexts = info.destructuredContexts || [];
-		this.destructuredContexts.forEach(name => {
-			this.scope.add(name, this.expression.dependencies);
-		});
-
 		this.children = mapChildren(compiler, this, this.scope, info.children);
 
 		this.else = info.else
@@ -90,17 +90,13 @@ export default class EachBlock extends Node {
 			this.block.getUniqueName(this.index); // this prevents name collisions (#1254)
 		}
 
-		this.contextProps = [
+		this.contextProps = this.contexts.map(prop => `${prop.key.name}: list[i]${prop.tail}`);
+
+		// TODO only add these if necessary
+		this.contextProps.push(
 			`${listName}: list`,
-			`${this.context}: list[i]`,
 			`${indexName}: i`
-		];
-
-		if (this.destructuredContexts) {
-			for (let i = 0; i < this.destructuredContexts.length; i += 1) {
-				this.contextProps.push(`${this.destructuredContexts[i]}: list[i][${i}]`);
-			}
-		}
+		);
 
 		this.compiler.target.blocks.push(this.block);
 		this.initChildren(this.block, stripWhitespace, nextSibling);
@@ -481,8 +477,7 @@ export default class EachBlock extends Node {
 		const { compiler } = this;
 		const { snippet } = this.expression;
 
-		const props = [`${this.context}: item`]
-			.concat(this.destructuredContexts.map((name, i) => `${name}: item[${i}]`));
+		const props = this.contexts.map(prop => `${prop.key.name}: item${prop.tail}`);
 
 		const getContext = this.index
 			? `(item, i) => Object.assign({}, ctx, { ${props.join(', ')}, ${this.index}: i })`

src/parse/read/context.ts

@@ -0,0 +1,114 @@
+import { Parser } from '../index';
+
+type Identifier = {
+	start: number;
+	end: number;
+	type: 'Identifier';
+	name: string;
+};
+
+type Property = {
+	start: number;
+	end: number;
+	type: 'Property';
+	key: Identifier;
+	value: Context;
+};
+
+type Context = {
+	start: number;
+	end: number;
+	type: 'Identifier' | 'ArrayPattern' | 'ObjectPattern';
+	name?: string;
+	elements?: Context[];
+	properties?: Property[];
+}
+
+function errorOnAssignmentPattern(parser: Parser) {
+	if (parser.eat('=')) {
+		parser.error({
+			code: 'invalid-assignment-pattern',
+			message: 'Assignment patterns are not supported'
+		}, parser.index - 1);
+	}
+}
+
+export default function readContext(parser: Parser) {
+	const context: Context = {
+		start: parser.index,
+		end: null,
+		type: null
+	};
+
+	if (parser.eat('[')) {
+		context.type = 'ArrayPattern';
+		context.elements = [];
+
+		do {
+			parser.allowWhitespace();
+			context.elements.push(readContext(parser));
+			parser.allowWhitespace();
+		} while (parser.eat(','));
+
+		errorOnAssignmentPattern(parser);
+		parser.eat(']', true);
+	}
+
+	else if (parser.eat('{')) {
+		context.type = 'ObjectPattern';
+		context.properties = [];
+
+		do {
+			parser.allowWhitespace();
+
+			const start = parser.index;
+			const name = parser.readIdentifier();
+			const key: Identifier = {
+				start,
+				end: parser.index,
+				type: 'Identifier',
+				name
+			};
+			parser.allowWhitespace();
+
+			const value = parser.eat(':')
+				? readContext(parser)
+				: key;
+
+			const property: Property = {
+				start,
+				end: value.end,
+				type: 'Property',
+				key,
+				value
+			};
+
+			context.properties.push(property);
+
+			parser.allowWhitespace();
+		} while (parser.eat(','));
+
+		errorOnAssignmentPattern(parser);
+		parser.eat('}', true);
+	}
+
+	else {
+		const name = parser.readIdentifier();
+		if (name) {
+			context.type = 'Identifier';
+			context.end = parser.index;
+			context.name = name;
+		}
+
+		else {
+			parser.error({
+				code: 'invalid-context',
+				message: 'Expected a name, array pattern or object pattern'
+			});
+		}
+
+		errorOnAssignmentPattern(parser);
+	}
+
+	return context;
+}

src/parse/state/mustache.ts

@@ -1,3 +1,4 @@
+import readContext from '../read/context';
 import readExpression from '../read/expression';
 import { whitespace } from '../../utils/patterns';
 import { trimStart, trimEnd } from '../../utils/trim';
@@ -248,40 +249,7 @@ export default function mustache(parser: Parser) {
 			parser.eat('as', true);
 			parser.requireWhitespace();
 
-			if (parser.eat('[')) {
-				parser.allowWhitespace();
-
-				block.destructuredContexts = [];
-
-				do {
-					parser.allowWhitespace();
-
-					const destructuredContext = parser.readIdentifier();
-					if (!destructuredContext) parser.error({
-						code: `expected-name`,
-						message: `Expected name`
-					});
-
-					block.destructuredContexts.push(destructuredContext);
-					parser.allowWhitespace();
-				} while (parser.eat(','));
-
-				if (!block.destructuredContexts.length) parser.error({
-					code: `expected-name`,
-					message: `Expected name`
-				});
-
-				block.context = block.destructuredContexts.join('_');
-
-				parser.allowWhitespace();
-				parser.eat(']', true);
-			} else {
-				block.context = parser.readIdentifier();
-				if (!block.context) parser.error({
-					code: `expected-name`,
-					message: `Expected name`
-				});
-			}
+			block.context = readContext(parser);
 
 			parser.allowWhitespace();
 

src/utils/unpackDestructuring.ts

@@ -0,0 +1,20 @@
+export default function unpackDestructuring(
+	contexts: Array<{ name: string, tail: string }>,
+	node: Node,
+	tail: string
+) {
+	if (node.type === 'Identifier') {
+		contexts.push({
+			key: node,
+			tail
+		});
+	} else if (node.type === 'ArrayPattern') {
+		node.elements.forEach((element, i) => {
+			unpackDestructuring(contexts, element, `${tail}[${i}]`);
+		});
+	} else if (node.type === 'ObjectPattern') {
+		node.properties.forEach((property) => {
+			unpackDestructuring(contexts, property.value, `${tail}.${property.key.name}`);
+		});
+	}
+}

src/validate/html/index.ts

@@ -8,6 +8,7 @@ import fuzzymatch from '../utils/fuzzymatch'
 import flattenReference from '../../utils/flattenReference';
 import { Validator } from '../index';
 import { Node } from '../../interfaces';
+import unpackDestructuring from '../../utils/unpackDestructuring';
 
 function isEmptyBlock(node: Node) {
 	if (!/Block$/.test(node.type) || !node.children) return false;
@@ -60,19 +61,17 @@ export default function validateHtml(validator: Validator, html: Node) {
 		}
 
 		else if (node.type === 'EachBlock') {
-			if (validator.helpers.has(node.context)) {
-				let c: number = node.expression.end;
-
-				// find start of context
-				while (/\s/.test(validator.source[c])) c += 1;
-				c += 2;
-				while (/\s/.test(validator.source[c])) c += 1;
-
-				validator.warn({ start: c, end: c + node.context.length }, {
-					code: `each-context-clash`,
-					message: `Context clashes with a helper. Rename one or the other to eliminate any ambiguity`
-				});
-			}
+			const contexts = [];
+			unpackDestructuring(contexts, node.context, '');
+
+			contexts.forEach(prop => {
+				if (validator.helpers.has(prop.key.name)) {
+					validator.warn(prop.key, {
+						code: `each-context-clash`,
+						message: `Context clashes with a helper. Rename one or the other to eliminate any ambiguity`
+					});
+				}
+			});
 		}
 
 		if (validator.options.dev && isEmptyBlock(node)) {

test/js/samples/deconflict-builtins/expected-bundle.js

@@ -250,8 +250,8 @@ function create_each_block(component, ctx) {
 
 function get_each_context(ctx, list, i) {
 	return assign(assign({}, ctx), {
-		each_value: list,
 		node: list[i],
+		each_value: list,
 		node_index: i
 	});
 }

test/js/samples/deconflict-builtins/expected.js

@@ -98,8 +98,8 @@ function create_each_block(component, ctx) {
 
 function get_each_context(ctx, list, i) {
 	return assign(assign({}, ctx), {
-		each_value: list,
 		node: list[i],
+		each_value: list,
 		node_index: i
 	});
 }

test/js/samples/each-block-changed-check/expected-bundle.js

@@ -297,8 +297,8 @@ function create_each_block(component, ctx) {
 
 function get_each_context(ctx, list, i) {
 	return assign(assign({}, ctx), {
-		each_value: list,
 		comment: list[i],
+		each_value: list,
 		i: i
 	});
 }

test/js/samples/each-block-changed-check/expected.js

@@ -143,8 +143,8 @@ function create_each_block(component, ctx) {
 
 function get_each_context(ctx, list, i) {
 	return assign(assign({}, ctx), {
-		each_value: list,
 		comment: list[i],
+		each_value: list,
 		i: i
 	});
 }

test/parser/samples/each-block-destructured/output.json

@@ -1,5 +1,4 @@
 {
-	"hash": "gtdm5e",
 	"html": {
 		"start": 0,
 		"end": 62,
@@ -54,11 +53,25 @@
 						]
 					}
 				],
-				"destructuredContexts": [
-					"key",
-					"value"
-				],
-				"context": "key_value"
+				"context": {
+					"start": 18,
+					"end": null,
+					"type": "ArrayPattern",
+					"elements": [
+						{
+							"start": 19,
+							"end": 22,
+							"type": "Identifier",
+							"name": "key"
+						},
+						{
+							"start": 24,
+							"end": 29,
+							"type": "Identifier",
+							"name": "value"
+						}
+					]
+				}
 			}
 		]
 	},

test/parser/samples/each-block-else/output.json

@@ -1,5 +1,4 @@
 {
-	"hash": "ljl07n",
 	"html": {
 		"start": 0,
 		"end": 77,
@@ -37,7 +36,12 @@
 						]
 					}
 				],
-				"context": "animal",
+				"context": {
+					"start": 18,
+					"end": 24,
+					"type": "Identifier",
+					"name": "animal"
+				},
 				"else": {
 					"start": 50,
 					"end": 70,

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

@@ -1,5 +1,4 @@
 {
-	"hash": "1143n2g",
 	"html": {
 		"start": 0,
 		"end": 58,
@@ -54,7 +53,12 @@
 						]
 					}
 				],
-				"context": "animal",
+				"context": {
+					"start": 18,
+					"end": 24,
+					"type": "Identifier",
+					"name": "animal"
+				},
 				"index": "i"
 			}
 		]

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

@@ -36,7 +36,12 @@
 						]
 					}
 				],
-				"context": "todo",
+				"context": {
+					"start": 16,
+					"end": 20,
+					"type": "Identifier",
+					"name": "todo"
+				},
 				"key": {
 					"type": "MemberExpression",
 					"start": 22,

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

@@ -1,5 +1,4 @@
 {
-	"hash": "mzeq0s",
 	"html": {
 		"start": 0,
 		"end": 50,
@@ -37,7 +36,12 @@
 						]
 					}
 				],
-				"context": "animal"
+				"context": {
+					"start": 18,
+					"end": 24,
+					"type": "Identifier",
+					"name": "animal"
+				}
 			}
 		]
 	},

test/parser/samples/unusual-identifier/output.json

@@ -1,5 +1,4 @@
 {
-	"hash": "8weqxs",
 	"html": {
 		"start": 0,
 		"end": 41,
@@ -37,7 +36,12 @@
 						]
 					}
 				],
-				"context": "𐊧"
+				"context": {
+					"start": 17,
+					"end": 19,
+					"type": "Identifier",
+					"name": "𐊧"
+				}
 			}
 		]
 	},

test/runtime/samples/each-block-destructured-object/_config.js

@@ -0,0 +1,22 @@
+export default {
+	data: {
+		animalPawsEntries: [
+			{ animal: 'raccoon', pawType: 'hands' },
+			{ animal: 'eagle', pawType: 'wings' }
+		]
+	},
+
+	html: `
+		<p>raccoon: hands</p>
+		<p>eagle: wings</p>
+	`,
+
+	test ( assert, component, target ) {
+		component.set({
+			animalPawsEntries: [{ animal: 'cow', pawType: 'hooves' }]
+		});
+		assert.htmlEqual( target.innerHTML, `
+			<p>cow: hooves</p>
+		`);
+	},
+};

test/runtime/samples/each-block-destructured-object/main.html

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