couple of fixes

src/compiler/compile/render_dom/wrappers/Title.ts

@@ -3,11 +3,12 @@ import Wrapper from './shared/Wrapper';
 import Renderer from '../Renderer';
 import Block from '../Block';
 import Title from '../../nodes/Title';
-import { stringify } from '../../utils/stringify';
+import { stringify, string_literal } from '../../utils/stringify';
 import add_to_set from '../../utils/add_to_set';
 import Text from '../../nodes/Text';
 import { Identifier } from 'estree';
 import { changed } from './shared/changed';
+import MustacheTag from '../../nodes/MustacheTag';
 
 export default class TitleWrapper extends Wrapper {
 	node: Title;
@@ -41,25 +42,21 @@ export default class TitleWrapper extends Wrapper {
 				add_to_set(all_dependencies, expression.dependencies);
 			} else {
 				// '{foo} {bar}' — treat as string concatenation
-				value =
+				value = this.node.children
-					(this.node.children[0].type === 'Text' ? '' : `"" + `) +
+					.map(chunk => {
-					this.node.children
+						if (chunk.type === 'Text') return string_literal(chunk.data);
-						.map((chunk) => {
+
-							if (chunk.type === 'Text') {
+						(chunk as MustacheTag).expression.dependencies.forEach(d => {
-								return stringify(chunk.data);
-							} else {
-								// @ts-ignore todo: check this
-								const snippet = chunk.expression.manipulate(block);
-								// @ts-ignore todo: check this
-								chunk.expression.dependencies.forEach(d => {
 							all_dependencies.add(d);
 						});
 
-								// @ts-ignore todo: check this
+						return (chunk as MustacheTag).expression.manipulate(block);
-								return chunk.expression.get_precedence() <= 13 ? `(${snippet})` : snippet;
-							}
 					})
-						.join(' + ');
+					.reduce((lhs, rhs) => x`${lhs} + ${rhs}`);
+
+				if (this.node.children[0].type !== 'Text') {
+					value = x`"" + ${value}`;
+				}
 			}
 
 			const last = this.node.should_cache && block.get_unique_name(
@@ -68,7 +65,7 @@ export default class TitleWrapper extends Wrapper {
 
 			if (this.node.should_cache) block.add_variable(last);
 
-			const init = this.node.should_cache ? `${last} = ${value}` : value;
+			const init = this.node.should_cache ? x`${last} = ${value}` : value;
 
 			block.chunks.init.push(
 				b`@_document.title = ${init};`

src/compiler/compile/render_dom/wrappers/shared/bind_this.ts

@@ -40,11 +40,14 @@ export default function bind_this(component: Component, block: Block, binding: B
 			`;
 	}
 
-	const contextual_dependencies = Array.from(binding.expression.contextual_dependencies);
+	const contextual_dependencies: Identifier[] = Array.from(binding.expression.contextual_dependencies).map(name => ({
+		type: 'Identifier',
+		name
+	}));
 
 	if (contextual_dependencies.length) {
 		component.partly_hoisted.push(b`
-			function ${fn}(${['$$value', ...contextual_dependencies]}) {
+			function ${fn}($$value, ${contextual_dependencies}) {
 				if (${lhs} === $$value) return;
 				@binding_callbacks[$$value ? 'unshift' : 'push'](() => {
 					${body}
@@ -53,8 +56,7 @@ export default function bind_this(component: Component, block: Block, binding: B
 		`);
 
 		const args = [];
-		for (const arg of contextual_dependencies) {
+		for (const id of contextual_dependencies) {
-			const id: Identifier = { type: 'Identifier', name: arg };
 			args.push(id);
 			block.add_variable(id, x`#ctx.${id}`);
 		}
@@ -63,11 +65,13 @@ export default function bind_this(component: Component, block: Block, binding: B
 		const unassign = block.get_unique_name(`unassign_${variable.name}`);
 
 		block.chunks.init.push(b`
-			const ${assign} = () => #ctx.${fn}(${[variable].concat(args)});
+			const ${assign} = () => #ctx.${fn}(${variable}, ${args});
-			const ${unassign} = () => #ctx.${fn}(${['null'].concat(args)});
+			const ${unassign} = () => #ctx.${fn}(null, ${args});
 		`);
 
-		const condition = Array.from(contextual_dependencies).map(name => `${name} !== #ctx.${name}`).join(' || ');
+		const condition = Array.from(contextual_dependencies)
+			.map(name => x`${name} !== #ctx.${name}`)
+			.reduce((lhs, rhs) => x`${lhs} || ${rhs}`);
 
 		// we push unassign and unshift assign so that references are
 		// nulled out before they're created, to avoid glitches