handle single identifiers in {@debug} tags

src/compile/nodes/DebugTag.ts

@@ -3,18 +3,17 @@ import Tag from './shared/Tag';
 import Block from '../dom/Block';
 import Expression from './shared/Expression';
 import deindent from '../../utils/deindent';
+import addToSet from '../../utils/addToSet';
 
 export default class DebugTag extends Node {
-	expression: Expression;
-	
+	expressions: Expression[];
+
 	constructor(compiler, parent, scope, info) {
 		super(compiler, parent, scope, info);
-		if (info.expression !== null)
-			// Debug when expression nodes change		
-			this.expression = new Expression(compiler, parent, scope, info.expression);
-		else
-			// "Debug all"
-			this.expression = info.expression
+
+		this.expressions = info.identifiers.map(node => {
+			return new Expression(compiler, parent, scope, node);
+		});
 	}
 
 	build(
@@ -23,15 +22,18 @@ export default class DebugTag extends Node {
 		parentNodes: string,
 	) {
 		// Debug all
-		if (this.expression === null) {
+		if (this.expressions.length === 0) {
 			block.builders.create.addLine('debugger;');
 			block.builders.update.addLine('debugger;');
 		} else {
-			const { dependencies } = this.expression;
+			const dependencies = new Set();
+			this.expressions.forEach(expression => {
+				addToSet(dependencies, expression.dependencies);
+			});
 
 			const condition = [...dependencies].map(d => `changed.${d}`).join(' || ');
 
-			const identifiers = this.expression.node.expressions.map(e => e.name).join(', ');
+			const identifiers = this.expressions.map(e => e.node.name).join(', ');
 
 			block.builders.update.addBlock(deindent`
 				if (${condition}) {

src/parse/state/mustache.ts

@@ -314,28 +314,36 @@ export default function mustache(parser: Parser) {
 			expression,
 		});
 	} else if (parser.eat('@debug')) {
-		let expression;
+		let identifiers;
 
 		// Implies {@debug} which indicates "debug all"
-		if (/\s*}/.test(parser.template[parser.index]))
-			expression = null;
-		else
-			expression = readExpression(parser);				
-
-		if (expression !== null && expression.type !== 'SequenceExpression')
-			parser.error({
-				code: 'invalid-debug-args',
-				message: '{@debug ...} arguments must be identifers, not arbitrary expressions'
-			}, expression.start);
+		if (parser.read(/\s*}/)) {
+			identifiers = [];
+		} else {
+			const expression = readExpression(parser);
+
+			identifiers = expression.type === 'SequenceExpression'
+				? expression.expressions
+				: [expression];
+
+			identifiers.forEach(node => {
+				if (node.type !== 'Identifier') {
+					parser.error({
+						code: 'invalid-debug-args',
+						message: '{@debug ...} arguments must be identifiers, not arbitrary expressions'
+					}, node.start);
+				}
+			});
 
-		parser.allowWhitespace();
-		parser.eat('}', true);
+			parser.allowWhitespace();
+			parser.eat('}', true);
+		}
 
 		parser.current().children.push({
 			start,
 			end: parser.index,
 			type: 'DebugTag',
-			expression,
+			identifiers
 		});
 	} else {
 		const expression = readExpression(parser);

test/js/samples/debug-foo/expected-bundle.js

@@ -0,0 +1,290 @@
+function noop() {}
+
+function assign(tar, src) {
+	for (var k in src) tar[k] = src[k];
+	return tar;
+}
+
+function append(target, node) {
+	target.appendChild(node);
+}
+
+function insert(target, node, anchor) {
+	target.insertBefore(node, anchor);
+}
+
+function detachNode(node) {
+	node.parentNode.removeChild(node);
+}
+
+function destroyEach(iterations, detach) {
+	for (var i = 0; i < iterations.length; i += 1) {
+		if (iterations[i]) iterations[i].d(detach);
+	}
+}
+
+function createElement(name) {
+	return document.createElement(name);
+}
+
+function createText(data) {
+	return document.createTextNode(data);
+}
+
+function setData(text, data) {
+	text.data = '' + data;
+}
+
+function blankObject() {
+	return Object.create(null);
+}
+
+function destroy(detach) {
+	this.destroy = noop;
+	this.fire('destroy');
+	this.set = noop;
+
+	this._fragment.d(detach !== false);
+	this._fragment = null;
+	this._state = {};
+}
+
+function _differs(a, b) {
+	return a != a ? b == b : a !== b || ((a && typeof a === 'object') || typeof a === 'function');
+}
+
+function fire(eventName, data) {
+	var handlers =
+		eventName in this._handlers && this._handlers[eventName].slice();
+	if (!handlers) return;
+
+	for (var i = 0; i < handlers.length; i += 1) {
+		var handler = handlers[i];
+
+		if (!handler.__calling) {
+			try {
+				handler.__calling = true;
+				handler.call(this, data);
+			} finally {
+				handler.__calling = false;
+			}
+		}
+	}
+}
+
+function get() {
+	return this._state;
+}
+
+function init(component, options) {
+	component._handlers = blankObject();
+	component._bind = options._bind;
+
+	component.options = options;
+	component.root = options.root || component;
+	component.store = options.store || component.root.store;
+}
+
+function on(eventName, handler) {
+	var handlers = this._handlers[eventName] || (this._handlers[eventName] = []);
+	handlers.push(handler);
+
+	return {
+		cancel: function() {
+			var index = handlers.indexOf(handler);
+			if (~index) handlers.splice(index, 1);
+		}
+	};
+}
+
+function set(newState) {
+	this._set(assign({}, newState));
+	if (this.root._lock) return;
+	this.root._lock = true;
+	callAll(this.root._beforecreate);
+	callAll(this.root._oncreate);
+	callAll(this.root._aftercreate);
+	this.root._lock = false;
+}
+
+function _set(newState) {
+	var oldState = this._state,
+		changed = {},
+		dirty = false;
+
+	for (var key in newState) {
+		if (this._differs(newState[key], oldState[key])) changed[key] = dirty = true;
+	}
+	if (!dirty) return;
+
+	this._state = assign(assign({}, oldState), newState);
+	this._recompute(changed, this._state);
+	if (this._bind) this._bind(changed, this._state);
+
+	if (this._fragment) {
+		this.fire("state", { changed: changed, current: this._state, previous: oldState });
+		this._fragment.p(changed, this._state);
+		this.fire("update", { changed: changed, current: this._state, previous: oldState });
+	}
+}
+
+function callAll(fns) {
+	while (fns && fns.length) fns.shift()();
+}
+
+function _mount(target, anchor) {
+	this._fragment[this._fragment.i ? 'i' : 'm'](target, anchor || null);
+}
+
+var proto = {
+	destroy,
+	get,
+	fire,
+	on,
+	set,
+	_recompute: noop,
+	_set,
+	_mount,
+	_differs
+};
+
+/* generated by Svelte vX.Y.Z */
+
+function create_main_fragment(component, ctx) {
+	var text, p, text_1, text_2;
+
+	var each_value = ctx.things;
+
+	var each_blocks = [];
+
+	for (var i = 0; i < each_value.length; i += 1) {
+		each_blocks[i] = create_each_block(component, get_each_context(ctx, each_value, i));
+	}
+
+	return {
+		c() {
+			for (var i = 0; i < each_blocks.length; i += 1) {
+				each_blocks[i].c();
+			}
+
+			text = createText("\n\n");
+			p = createElement("p");
+			text_1 = createText("foo: ");
+			text_2 = createText(ctx.foo);
+		},
+
+		m(target, anchor) {
+			for (var i = 0; i < each_blocks.length; i += 1) {
+				each_blocks[i].m(target, anchor);
+			}
+
+			insert(target, text, anchor);
+			insert(target, p, anchor);
+			append(p, text_1);
+			append(p, text_2);
+		},
+
+		p(changed, ctx) {
+			if (changed.things) {
+				each_value = ctx.things;
+
+				for (var i = 0; i < each_value.length; i += 1) {
+					const child_ctx = get_each_context(ctx, each_value, i);
+
+					if (each_blocks[i]) {
+						each_blocks[i].p(changed, child_ctx);
+					} else {
+						each_blocks[i] = create_each_block(component, child_ctx);
+						each_blocks[i].c();
+						each_blocks[i].m(text.parentNode, text);
+					}
+				}
+
+				for (; i < each_blocks.length; i += 1) {
+					each_blocks[i].d(1);
+				}
+				each_blocks.length = each_value.length;
+			}
+
+			if (changed.foo) {
+				setData(text_2, ctx.foo);
+			}
+		},
+
+		d(detach) {
+			destroyEach(each_blocks, detach);
+
+			if (detach) {
+				detachNode(text);
+				detachNode(p);
+			}
+		}
+	};
+}
+
+// (1:0) {#each things as thing}
+function create_each_block(component, ctx) {
+	var span, text_value = ctx.thing.name, text, text_1;
+
+	return {
+		c() {
+			span = createElement("span");
+			text = createText(text_value);
+			text_1 = createText("\n\t");
+
+			const { foo } = ctx;
+			console.log({ foo });
+			debugger;
+		},
+
+		m(target, anchor) {
+			insert(target, span, anchor);
+			append(span, text);
+			insert(target, text_1, anchor);
+		},
+
+		p(changed, ctx) {
+			if ((changed.things) && text_value !== (text_value = ctx.thing.name)) {
+				setData(text, text_value);
+			}
+
+			if (changed.foo) {
+				const { foo } = ctx;
+				console.log({ foo });
+				debugger;
+			}
+		},
+
+		d(detach) {
+			if (detach) {
+				detachNode(span);
+				detachNode(text_1);
+			}
+		}
+	};
+}
+
+function get_each_context(ctx, list, i) {
+	const child_ctx = Object.create(ctx);
+	child_ctx.thing = list[i];
+	child_ctx.each_value = list;
+	child_ctx.thing_index = i;
+	return child_ctx;
+}
+
+function SvelteComponent(options) {
+	init(this, options);
+	this._state = assign({}, options.data);
+	this._intro = true;
+
+	this._fragment = create_main_fragment(this, this._state);
+
+	if (options.target) {
+		this._fragment.c();
+		this._mount(options.target, options.anchor);
+	}
+}
+
+assign(SvelteComponent.prototype, proto);
+
+export default SvelteComponent;