From 1091d23ed171e833fc7e1cb4dfde82bdcb34ba15 Mon Sep 17 00:00:00 2001
From: Richard Harris <richard.a.harris@gmail.com>
Date: Sat, 14 Sep 2019 18:58:26 -0400
Subject: [PATCH] some annoying typescript stuff

---
 package-lock.json                             | 23 ++----
 package.json                                  |  4 +-
 rollup.config.js                              |  5 +-
 src/compiler/compile/Component.ts             | 78 +++++++++----------
 src/compiler/compile/create_module.ts         | 11 +--
 src/compiler/compile/css/Selector.ts          | 32 ++++----
 src/compiler/compile/css/Stylesheet.ts        | 51 ++++++------
 .../compile/css/gather_possible_values.ts     |  2 +-
 src/compiler/compile/css/interfaces.ts        |  6 ++
 src/compiler/compile/nodes/EachBlock.ts       | 33 ++++----
 src/compiler/compile/nodes/EventHandler.ts    | 18 +++--
 src/compiler/compile/nodes/Let.ts             |  2 +-
 .../compile/nodes/shared/Expression.ts        | 26 ++++---
 .../compile/nodes/shared/map_children.ts      |  4 +-
 src/compiler/compile/render_dom/Block.ts      | 34 ++++----
 src/compiler/compile/render_dom/Renderer.ts   | 12 +--
 src/compiler/compile/render_dom/index.ts      | 48 ++++++------
 .../compile/render_dom/wrappers/AwaitBlock.ts |  4 +-
 .../compile/render_dom/wrappers/Body.ts       |  2 +-
 .../compile/render_dom/wrappers/DebugTag.ts   |  2 +-
 .../compile/render_dom/wrappers/EachBlock.ts  | 17 ++--
 .../render_dom/wrappers/Element/Binding.ts    | 38 +++++----
 .../render_dom/wrappers/Element/index.ts      | 10 +--
 .../compile/render_dom/wrappers/IfBlock.ts    |  5 +-
 .../wrappers/InlineComponent/index.ts         | 10 +--
 .../render_dom/wrappers/MustacheTag.ts        |  4 +-
 .../render_dom/wrappers/RawMustacheTag.ts     |  4 +-
 .../compile/render_dom/wrappers/Slot.ts       |  2 +-
 .../compile/render_dom/wrappers/Text.ts       |  5 +-
 .../compile/render_dom/wrappers/Title.ts      |  2 +-
 .../compile/render_dom/wrappers/Window.ts     |  6 +-
 .../compile/render_dom/wrappers/shared/Tag.ts |  4 +-
 .../render_dom/wrappers/shared/Wrapper.ts     | 10 +--
 .../render_dom/wrappers/shared/bind_this.ts   |  4 +-
 .../compile/render_ssr/handlers/EachBlock.ts  |  2 +-
 src/compiler/compile/render_ssr/index.ts      | 59 +++++++-------
 .../compile/utils/flatten_reference.ts        | 12 ++-
 src/compiler/compile/utils/get_object.ts      |  8 +-
 src/compiler/compile/utils/invalidate.ts      |  4 +-
 src/compiler/compile/utils/scope.ts           | 52 +++++++------
 src/compiler/compile/utils/tail.ts            |  7 --
 src/compiler/compile/utils/unwrap_parens.ts   |  6 --
 src/compiler/interfaces.ts                    | 41 +++++++---
 src/compiler/parse/index.ts                   | 12 +--
 src/compiler/parse/read/script.ts             | 14 ++--
 src/compiler/parse/read/style.ts              | 14 ++--
 src/compiler/parse/state/mustache.ts          | 10 +--
 src/compiler/parse/state/tag.ts               | 10 +--
 48 files changed, 397 insertions(+), 372 deletions(-)
 create mode 100644 src/compiler/compile/css/interfaces.ts
 delete mode 100644 src/compiler/compile/utils/tail.ts
 delete mode 100644 src/compiler/compile/utils/unwrap_parens.ts

diff --git a/package-lock.json b/package-lock.json
index 827178a325..dccb96164f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -502,27 +502,20 @@
       "dev": true
     },
     "code-red": {
-      "version": "0.0.8",
-      "resolved": "https://registry.npmjs.org/code-red/-/code-red-0.0.8.tgz",
-      "integrity": "sha512-wvKPondTM1H6MoUnz5tj6z1xawzmaulkC0qLv5S1KLkShWgRybgIdvGyVr5pPQt2ovpdmh6BcpRXXoqs5X8tcA==",
+      "version": "0.0.9",
+      "resolved": "https://registry.npmjs.org/code-red/-/code-red-0.0.9.tgz",
+      "integrity": "sha512-xQVOUxMYfFXgkW/VA1raehj+YH8CV98c8XG5cFhpeEYoO8fIjr4KM4E0Ov6lLC2rSu5qtMWmrcA1gveZwg8r1w==",
       "dev": true,
       "requires": {
         "acorn": "^7.0.0",
-        "estree-walker": "^0.6.1",
         "is-reference": "^1.1.3",
         "periscopic": "^1.0.0",
         "source-map": "^0.7.3"
       },
       "dependencies": {
         "astring": {
-          "version": "github:Rich-Harris/astring#ff83f5e4e75b304cdd428ada4a71372276b0084d",
-          "from": "github:Rich-Harris/astring#ff83f5e4e75b304cdd428ada4a71372276b0084d"
-        },
-        "estree-walker": {
-          "version": "0.6.1",
-          "resolved": "https://registry.npmjs.org/estree-walker/-/estree-walker-0.6.1.tgz",
-          "integrity": "sha512-SqmZANLWS0mnatqbSfRP5g8OXZC12Fgg1IwNtLsyHDzJizORW4khDfjPqJZsemPWBB2uqykUah5YpQ6epsqC/w==",
-          "dev": true
+          "version": "github:Rich-Harris/astring#00fa527b66cc1b57efb2a4b9052dd4e190ae3590",
+          "from": "github:Rich-Harris/astring#00fa527b66cc1b57efb2a4b9052dd4e190ae3590"
         },
         "source-map": {
           "version": "0.7.3",
@@ -1212,9 +1205,9 @@
       "dev": true
     },
     "estree-walker": {
-      "version": "0.7.0",
-      "resolved": "https://registry.npmjs.org/estree-walker/-/estree-walker-0.7.0.tgz",
-      "integrity": "sha512-6BzTIhsjm2jnqLO+O23aaiDGr9jsrgwT1ObAIEebwvbJthCoF5T1MtybbCx540r2U5fsn/8IIv7ZWqMqTHuu6Q==",
+      "version": "0.8.1",
+      "resolved": "https://registry.npmjs.org/estree-walker/-/estree-walker-0.8.1.tgz",
+      "integrity": "sha512-H6cJORkqvrNziu0KX2hqOMAlA2CiuAxHeGJXSIoKA/KLv229Dw806J3II6mKTm5xiDX1At1EXCfsOQPB+tMB+g==",
       "dev": true
     },
     "esutils": {
diff --git a/package.json b/package.json
index 0ea531048b..f86ff68cd0 100644
--- a/package.json
+++ b/package.json
@@ -63,13 +63,13 @@
     "acorn": "^7.0.0",
     "agadoo": "^1.0.1",
     "c8": "^5.0.1",
-    "code-red": "0.0.8",
+    "code-red": "0.0.9",
     "codecov": "^3.5.0",
     "css-tree": "1.0.0-alpha22",
     "eslint": "^6.3.0",
     "eslint-plugin-import": "^2.18.2",
     "eslint-plugin-svelte3": "^2.7.3",
-    "estree-walker": "^0.7.0",
+    "estree-walker": "^0.8.1",
     "is-reference": "^1.1.3",
     "jsdom": "^15.1.1",
     "kleur": "^3.0.3",
diff --git a/rollup.config.js b/rollup.config.js
index 7cce25e24c..25cc581044 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -20,8 +20,9 @@ const ts_plugin = is_publish
 
 const external = id => id.startsWith('svelte/');
 
-const inlined_estree = fs.readFileSync('./node_modules/estree-walker/index.d.ts', 'utf-8').replace(/declare.*\{((.|[\n\r])+)\}/m, '$1');
-fs.writeFileSync(`./compiler.d.ts`, `export { compile, parse, preprocess, VERSION } from './types/compiler/index';\n${inlined_estree}`);
+// const inlined_estree = fs.readFileSync('./node_modules/estree-walker/index.d.ts', 'utf-8').replace(/declare.*\{((.|[\n\r])+)\}/m, '$1');
+// fs.writeFileSync(`./compiler.d.ts`, `export { compile, parse, preprocess, VERSION } from './types/compiler/index';\n${inlined_estree}`);
+fs.writeFileSync(`./compiler.d.ts`, `export { compile, parse, preprocess, VERSION } from './types/compiler/index';`);
 
 export default [
 	/* runtime */
diff --git a/src/compiler/compile/Component.ts b/src/compiler/compile/Component.ts
index 29e05c7987..4262b07fdd 100644
--- a/src/compiler/compile/Component.ts
+++ b/src/compiler/compile/Component.ts
@@ -15,7 +15,7 @@ import Stylesheet from './css/Stylesheet';
 import { test } from '../config';
 import Fragment from './nodes/Fragment';
 import internal_exports from './internal_exports';
-import { Node, Ast, CompileOptions, Var, Warning, Identifier } from '../interfaces';
+import { Ast, CompileOptions, Var, Warning } from '../interfaces';
 import error from '../utils/error';
 import get_code_frame from '../utils/get_code_frame';
 import flatten_reference from './utils/flatten_reference';
@@ -23,9 +23,8 @@ import is_reference from 'is-reference';
 import TemplateScope from './nodes/shared/TemplateScope';
 import fuzzymatch from '../utils/fuzzymatch';
 import get_object from './utils/get_object';
-import unwrap_parens from './utils/unwrap_parens';
 import Slot from './nodes/Slot';
-import { Node as ESTreeNode } from 'estree';
+import { Node, ImportDeclaration, Identifier, Program, ExpressionStatement, AssignmentExpression } from 'estree';
 import add_to_set from './utils/add_to_set';
 import check_graph_for_cycles from './utils/check_graph_for_cycles';
 import { print, x } from 'code-red';
@@ -46,7 +45,7 @@ childKeys.Attribute = ['value'];
 childKeys.ExportNamedDeclaration = ['declaration', 'specifiers'];
 
 function remove_node(
-	body: Node,
+	body: Node[],
 	node: Node
 ) {
 	const i = body.indexOf(node);
@@ -78,14 +77,14 @@ export default class Component {
 	vars: Var[] = [];
 	var_lookup: Map<string, Var> = new Map();
 
-	imports: Node[] = [];
+	imports: ImportDeclaration[] = [];
 	module_javascript: string;
 	javascript: string;
 
 	hoistable_nodes: Set<Node> = new Set();
 	node_for_declaration: Map<string, Node> = new Map();
-	partly_hoisted: Node[] = [];
-	fully_hoisted: Node[] = [];
+	partly_hoisted: (Node | Node[])[] = [];
+	fully_hoisted: (Node | Node[])[] = [];
 	reactive_declarations: Array<{
 		assignees: Set<string>;
 		dependencies: Set<string>;
@@ -589,7 +588,7 @@ export default class Component {
 		walk(script.content, {
 			enter(node) {
 				if (node.type === 'LabeledStatement' && node.label.name === '$') {
-					component.warn(node, {
+					component.warn(node as any, {
 						code: 'module-script-reactive-declaration',
 						message: '$: has no effect in a module script',
 					});
@@ -602,23 +601,25 @@ export default class Component {
 
 		scope.declarations.forEach((node, name) => {
 			if (name[0] === '$') {
-				this.error(node, {
+				this.error(node as any, {
 					code: 'illegal-declaration',
 					message: `The $ prefix is reserved, and cannot be used for variable and import names`,
 				});
 			}
 
+			const writable = node.type === 'VariableDeclaration' && (node.kind === 'var' || node.kind === 'let');
+
 			this.add_var({
 				name,
 				module: true,
 				hoistable: true,
-				writable: node.kind === 'var' || node.kind === 'let',
+				writable
 			});
 		});
 
 		globals.forEach((node, name) => {
 			if (name[0] === '$') {
-				this.error(node, {
+				this.error(node as any, {
 					code: 'illegal-subscription',
 					message: `Cannot reference store value inside <script context="module">`,
 				});
@@ -644,7 +645,7 @@ export default class Component {
 			if (node.type !== 'LabeledStatement') return;
 			if (node.body.type !== 'ExpressionStatement') return;
 
-			const expression = unwrap_parens(node.body.expression);
+			const { expression } = node.body;
 			if (expression.type !== 'AssignmentExpression') return;
 
 			extract_names(expression.left).forEach(name => {
@@ -662,17 +663,19 @@ export default class Component {
 
 		instance_scope.declarations.forEach((node, name) => {
 			if (name[0] === '$') {
-				this.error(node, {
+				this.error(node as any, {
 					code: 'illegal-declaration',
 					message: `The $ prefix is reserved, and cannot be used for variable and import names`,
 				});
 			}
 
+			const writable = node.type === 'VariableDeclaration' && (node.kind === 'var' || node.kind === 'let');
+
 			this.add_var({
 				name,
 				initialised: instance_scope.initialised_declarations.has(name),
 				hoistable: /^Import/.test(node.type),
-				writable: node.kind === 'var' || node.kind === 'let',
+				writable
 			});
 
 			this.node_for_declaration.set(name, node);
@@ -696,7 +699,7 @@ export default class Component {
 				});
 			} else if (name[0] === '$') {
 				if (name === '$' || name[1] === '$') {
-					this.error(node, {
+					this.error(node as any, {
 						code: 'illegal-global',
 						message: `${name} is an illegal variable name`
 					});
@@ -749,20 +752,12 @@ export default class Component {
 					scope = map.get(node);
 				}
 
-				let names;
-				let deep = false;
-
-				if (node.type === 'AssignmentExpression') {
-					deep = node.left.type === 'MemberExpression';
+				if (node.type === 'AssignmentExpression' || node.type === 'UpdateExpression') {
+					const assignee = node.type === 'AssignmentExpression' ? node.left : node.argument;
+					const names = extract_names(assignee);
 
-					names = deep
-						? [get_object(node.left).name]
-						: extract_names(node.left);
-				} else if (node.type === 'UpdateExpression') {
-					names = [get_object(node.argument).name];
-				}
+					const deep = assignee.type === 'MemberExpression';
 
-				if (names) {
 					names.forEach(name => {
 						if (scope.find_owner(name) === instance_scope) {
 							const variable = component.var_lookup.get(name);
@@ -797,13 +792,13 @@ export default class Component {
 					node.label.name === '$' &&
 					parent.type !== 'Program'
 				) {
-					component.warn(node, {
+					component.warn(node as any, {
 						code: 'non-top-level-reactive-declaration',
 						message: '$: has no effect outside of the top-level',
 					});
 				}
 
-				if (is_reference(node as ESTreeNode, parent as ESTreeNode)) {
+				if (is_reference(node as Node, parent as Node)) {
 					const object = get_object(node);
 					const { name } = object;
 
@@ -891,7 +886,7 @@ export default class Component {
 
 									if (variable.export_name) {
 										// TODO is this still true post-#3539?
-										component.error(declarator, {
+										component.error(declarator as any, {
 											code: 'destructured-prop',
 											message: `Cannot declare props in destructured declaration`,
 										});
@@ -939,13 +934,13 @@ export default class Component {
 				}
 			},
 
-			leave(node, _parent, _key, index) {
+			leave(node, parent, _key, index) {
 				if (map.has(node)) {
 					scope = scope.parent;
 				}
 
 				if (node.type === 'ExportNamedDeclaration' && node.declaration) {
-					_parent.body[index] = node.declaration;
+					(parent as Program).body[index] = node.declaration;
 				}
 			},
 		});
@@ -975,14 +970,16 @@ export default class Component {
 					if (!d.init) return false;
 					if (d.init.type !== 'Literal') return false;
 
-					const v = this.var_lookup.get(d.id.name);
+					const { name } = d.id as Identifier;
+
+					const v = this.var_lookup.get(name);
 					if (v.reassigned) return false;
 					if (v.export_name) return false;
 
-					if (this.var_lookup.get(d.id.name).reassigned) return false;
+					if (this.var_lookup.get(name).reassigned) return false;
 					if (
 						this.vars.find(
-							variable => variable.name === d.id.name && variable.module
+							variable => variable.name === name && variable.module
 						)
 					)
 						return false;
@@ -992,7 +989,7 @@ export default class Component {
 
 				if (all_hoistable) {
 					node.declarations.forEach(d => {
-						const variable = this.var_lookup.get(d.id.name);
+						const variable = this.var_lookup.get((d.id as Identifier).name);
 						variable.hoistable = true;
 					});
 
@@ -1041,7 +1038,7 @@ export default class Component {
 						scope = map.get(node);
 					}
 
-					if (is_reference(node as ESTreeNode, parent as ESTreeNode)) {
+					if (is_reference(node as Node, parent as Node)) {
 						const { name } = flatten_reference(node);
 						const owner = scope.find_owner(name);
 
@@ -1138,7 +1135,7 @@ export default class Component {
 						} else if (node.type === 'UpdateExpression') {
 							const identifier = get_object(node.argument);
 							assignees.add(identifier.name);
-						} else if (is_reference(node as ESTreeNode, parent as ESTreeNode)) {
+						} else if (is_reference(node as Node, parent as Node)) {
 							const identifier = get_object(node);
 							if (!assignee_nodes.has(identifier)) {
 								const { name } = identifier;
@@ -1166,9 +1163,8 @@ export default class Component {
 					},
 				});
 
-				const expression =
-					node.body.expression && unwrap_parens(node.body.expression);
-				const declaration = expression && expression.left;
+				const { expression } = node.body as ExpressionStatement;
+				const declaration = expression && (expression as AssignmentExpression).left;
 
 				unsorted_reactive_declarations.push({
 					assignees,
diff --git a/src/compiler/compile/create_module.ts b/src/compiler/compile/create_module.ts
index 0a70b42f2d..87d7da0dc7 100644
--- a/src/compiler/compile/create_module.ts
+++ b/src/compiler/compile/create_module.ts
@@ -1,6 +1,7 @@
 import list from '../utils/list';
-import { ModuleFormat, Node, Identifier } from '../interfaces';
+import { ModuleFormat } from '../interfaces';
 import { b, x } from 'code-red';
+import { Identifier, ImportDeclaration } from 'estree';
 
 const wrappers = { esm, cjs };
 
@@ -17,7 +18,7 @@ export default function create_module(
 	sveltePath = 'svelte',
 	helpers: Array<{ name: string; alias: Identifier }>,
 	globals: Array<{ name: string; alias: Identifier }>,
-	imports: Node[],
+	imports: ImportDeclaration[],
 	module_exports: Export[]
 ) {
 	const internal_path = `${sveltePath}/internal`;
@@ -45,7 +46,7 @@ function esm(
 	internal_path: string,
 	helpers: Array<{ name: string; alias: Identifier }>,
 	globals: Array<{ name: string; alias: Identifier }>,
-	imports: Node[],
+	imports: ImportDeclaration[],
 	module_exports: Export[]
 ) {
 	const import_declaration = {
@@ -113,7 +114,7 @@ function cjs(
 	internal_path: string,
 	helpers: Array<{ name: string; alias: Identifier }>,
 	globals: Array<{ name: string; alias: Identifier }>,
-	imports: Node[],
+	imports: ImportDeclaration[],
 	module_exports: Export[]
 ) {
 	const internal_requires = {
@@ -172,7 +173,7 @@ function cjs(
 						method: false,
 						shorthand: false,
 						computed: false,
-						key: s.imported || { type: 'Identifier', name: 'default' },
+						key: s.type === 'ImportSpecifier' ? s.imported : { type: 'Identifier', name: 'default' },
 						value: s.local,
 						kind: 'init'
 					}))
diff --git a/src/compiler/compile/css/Selector.ts b/src/compiler/compile/css/Selector.ts
index 0d4ea82bb5..e6a00435d9 100644
--- a/src/compiler/compile/css/Selector.ts
+++ b/src/compiler/compile/css/Selector.ts
@@ -1,17 +1,17 @@
 import MagicString from 'magic-string';
 import Stylesheet from './Stylesheet';
 import { gather_possible_values, UNKNOWN } from './gather_possible_values';
-import { Node } from '../../interfaces';
+import { CssNode } from './interfaces';
 import Component from '../Component';
 
 export default class Selector {
-	node: Node;
+	node: CssNode;
 	stylesheet: Stylesheet;
 	blocks: Block[];
 	local_blocks: Block[];
 	used: boolean;
 
-	constructor(node: Node, stylesheet: Stylesheet) {
+	constructor(node: CssNode, stylesheet: Stylesheet) {
 		this.node = node;
 		this.stylesheet = stylesheet;
 
@@ -28,8 +28,8 @@ export default class Selector {
 		this.used = this.blocks[0].global;
 	}
 
-	apply(node: Node, stack: Node[]) {
-		const to_encapsulate: Node[] = [];
+	apply(node: CssNode, stack: CssNode[]) {
+		const to_encapsulate: CssNode[] = [];
 
 		apply_selector(this.stylesheet, this.local_blocks.slice(), node, stack.slice(), to_encapsulate);
 
@@ -126,7 +126,7 @@ export default class Selector {
 	}
 }
 
-function apply_selector(stylesheet: Stylesheet, blocks: Block[], node: Node, stack: Node[], to_encapsulate: any[]): boolean {
+function apply_selector(stylesheet: Stylesheet, blocks: Block[], node: CssNode, stack: CssNode[], to_encapsulate: any[]): boolean {
 	const block = blocks.pop();
 	if (!block) return false;
 
@@ -215,13 +215,13 @@ const operators = {
 	'*=': (value: string, flags: string) => new RegExp(value, flags)
 };
 
-function attribute_matches(node: Node, name: string, expected_value: string, operator: string, case_insensitive: boolean) {
+function attribute_matches(node: CssNode, name: string, expected_value: string, operator: string, case_insensitive: boolean) {
 	const spread = node.attributes.find(attr => attr.type === 'Spread');
 	if (spread) return true;
 
-	if (node.bindings.some((binding: Node) => binding.name === name)) return true;
+	if (node.bindings.some((binding: CssNode) => binding.name === name)) return true;
 
-	const attr = node.attributes.find((attr: Node) => attr.name === name);
+	const attr = node.attributes.find((attr: CssNode) => attr.name === name);
 	if (!attr) return false;
 	if (attr.is_true) return operator === null;
 	if (attr.chunks.length > 1) return true;
@@ -250,7 +250,7 @@ function class_matches(node, name: string) {
 	});
 }
 
-function unquote(value: Node) {
+function unquote(value: CssNode) {
 	if (value.type === 'Identifier') return value.name;
 	const str = value.value;
 	if (str[0] === str[str.length - 1] && str[0] === "'" || str[0] === '"') {
@@ -261,13 +261,13 @@ function unquote(value: Node) {
 
 class Block {
 	global: boolean;
-	combinator: Node;
-	selectors: Node[]
+	combinator: CssNode;
+	selectors: CssNode[]
 	start: number;
 	end: number;
 	should_encapsulate: boolean;
 
-	constructor(combinator: Node) {
+	constructor(combinator: CssNode) {
 		this.combinator = combinator;
 		this.global = false;
 		this.selectors = [];
@@ -278,7 +278,7 @@ class Block {
 		this.should_encapsulate = false;
 	}
 
-	add(selector: Node) {
+	add(selector: CssNode) {
 		if (this.selectors.length === 0) {
 			this.start = selector.start;
 			this.global = selector.type === 'PseudoClassSelector' && selector.name === 'global';
@@ -289,12 +289,12 @@ class Block {
 	}
 }
 
-function group_selectors(selector: Node) {
+function group_selectors(selector: CssNode) {
 	let block: Block = new Block(null);
 
 	const blocks = [block];
 
-	selector.children.forEach((child: Node) => {
+	selector.children.forEach((child: CssNode) => {
 		if (child.type === 'WhiteSpace' || child.type === 'Combinator') {
 			block = new Block(child);
 			blocks.push(block);
diff --git a/src/compiler/compile/css/Stylesheet.ts b/src/compiler/compile/css/Stylesheet.ts
index 5ae1de14be..8342c3fa21 100644
--- a/src/compiler/compile/css/Stylesheet.ts
+++ b/src/compiler/compile/css/Stylesheet.ts
@@ -2,20 +2,21 @@ import MagicString from 'magic-string';
 import { walk } from 'estree-walker';
 import Selector from './Selector';
 import Element from '../nodes/Element';
-import { Node, Ast } from '../../interfaces';
+import { Ast, TemplateNode } from '../../interfaces';
 import Component from '../Component';
+import { CssNode } from './interfaces';
 
 function remove_css_prefix(name: string): string {
 	return name.replace(/^-((webkit)|(moz)|(o)|(ms))-/, '');
 }
 
-const is_keyframes_node = (node: Node) =>
+const is_keyframes_node = (node: CssNode) =>
 	remove_css_prefix(node.name) === 'keyframes';
 
-const at_rule_has_declaration = ({ block }: Node): true =>
+const at_rule_has_declaration = ({ block }: CssNode): true =>
 	block &&
 	block.children &&
-	block.children.find((node: Node) => node.type === 'Declaration');
+	block.children.find((node: CssNode) => node.type === 'Declaration');
 
 function minify_declarations(
 	code: MagicString,
@@ -48,14 +49,14 @@ function hash(str: string): string {
 class Rule {
 	selectors: Selector[];
 	declarations: Declaration[];
-	node: Node;
+	node: CssNode;
 	parent: Atrule;
 
-	constructor(node: Node, stylesheet, parent?: Atrule) {
+	constructor(node: CssNode, stylesheet, parent?: Atrule) {
 		this.node = node;
 		this.parent = parent;
-		this.selectors = node.selector.children.map((node: Node) => new Selector(node, stylesheet));
-		this.declarations = node.block.children.map((node: Node) => new Declaration(node));
+		this.selectors = node.selector.children.map((node: CssNode) => new Selector(node, stylesheet));
+		this.declarations = node.block.children.map((node: CssNode) => new Declaration(node));
 	}
 
 	apply(node: Element, stack: Element[]) {
@@ -117,16 +118,16 @@ class Rule {
 }
 
 class Declaration {
-	node: Node;
+	node: CssNode;
 
-	constructor(node: Node) {
+	constructor(node: CssNode) {
 		this.node = node;
 	}
 
 	transform(code: MagicString, keyframes: Map<string, string>) {
 		const property = this.node.property && remove_css_prefix(this.node.property.toLowerCase());
 		if (property === 'animation' || property === 'animation-name') {
-			this.node.value.children.forEach((block: Node) => {
+			this.node.value.children.forEach((block: CssNode) => {
 				if (block.type === 'Identifier') {
 					const name = block.name;
 					if (keyframes.has(name)) {
@@ -155,11 +156,11 @@ class Declaration {
 }
 
 class Atrule {
-	node: Node;
+	node: CssNode;
 	children: Array<Atrule|Rule>;
 	declarations: Declaration[];
 
-	constructor(node: Node) {
+	constructor(node: CssNode) {
 		this.node = node;
 		this.children = [];
 		this.declarations = [];
@@ -191,7 +192,7 @@ class Atrule {
 			let c = this.node.start + (expression_char === '(' ? 6 : 7);
 			if (this.node.expression.start > c) code.remove(c, this.node.expression.start);
 
-			this.node.expression.children.forEach((query: Node) => {
+			this.node.expression.children.forEach((query: CssNode) => {
 				// TODO minify queries
 				c = query.end;
 			});
@@ -200,7 +201,7 @@ class Atrule {
 		} else if (this.node.name === 'supports') {
 			let c = this.node.start + 9;
 			if (this.node.expression.start - c > 1) code.overwrite(c, this.node.expression.start, ' ');
-			this.node.expression.children.forEach((query: Node) => {
+			this.node.expression.children.forEach((query: CssNode) => {
 				// TODO minify queries
 				c = query.end;
 			});
@@ -240,7 +241,7 @@ class Atrule {
 
 	transform(code: MagicString, id: string, keyframes: Map<string, string>) {
 		if (is_keyframes_node(this.node)) {
-			this.node.expression.children.forEach(({ type, name, start, end }: Node) => {
+			this.node.expression.children.forEach(({ type, name, start, end }: CssNode) => {
 				if (type === 'Identifier') {
 					if (name.startsWith('-global-')) {
 						code.remove(start, start + 8);
@@ -288,7 +289,7 @@ export default class Stylesheet {
 	children: Array<Rule|Atrule> = [];
 	keyframes: Map<string, string> = new Map();
 
-	nodes_with_css_class: Set<Node> = new Set();
+	nodes_with_css_class: Set<CssNode> = new Set();
 
 	constructor(source: string, ast: Ast, filename: string, dev: boolean) {
 		this.source = source;
@@ -305,8 +306,8 @@ export default class Stylesheet {
 			let depth = 0;
 			let current_atrule: Atrule = null;
 
-			walk(ast.css, {
-				enter: (node: Node) => {
+			walk(ast.css as any, {
+				enter: (node: any) => {
 					if (node.type === 'Atrule') {
 						const atrule = new Atrule(node);
 						stack.push(atrule);
@@ -318,7 +319,7 @@ export default class Stylesheet {
 						}
 
 						if (is_keyframes_node(node)) {
-							node.expression.children.forEach((expression: Node) => {
+							node.expression.children.forEach((expression: CssNode) => {
 								if (expression.type === 'Identifier' && !expression.name.startsWith('-global-')) {
 									this.keyframes.set(expression.name, `${this.id}-${expression.name}`);
 								}
@@ -346,7 +347,7 @@ export default class Stylesheet {
 					depth += 1;
 				},
 
-				leave: (node: Node) => {
+				leave: (node: any) => {
 					if (node.type === 'Atrule') {
 						stack.pop();
 						current_atrule = stack[stack.length - 1];
@@ -364,7 +365,7 @@ export default class Stylesheet {
 		if (!this.has_styles) return;
 
 		const stack: Element[] = [];
-		let parent: Node = node;
+		let parent: TemplateNode = node;
 		while (parent = parent.parent) {
 			if (parent.type === 'Element') stack.unshift(parent as Element);
 		}
@@ -376,7 +377,7 @@ export default class Stylesheet {
 	}
 
 	reify() {
-		this.nodes_with_css_class.forEach((node: Node) => {
+		this.nodes_with_css_class.forEach((node: Element) => {
 			node.add_css_class();
 		});
 	}
@@ -388,8 +389,8 @@ export default class Stylesheet {
 
 		const code = new MagicString(this.source);
 
-		walk(this.ast.css, {
-			enter: (node: Node) => {
+		walk(this.ast.css as any, {
+			enter: (node: any) => {
 				code.addSourcemapLocation(node.start);
 				code.addSourcemapLocation(node.end);
 			}
diff --git a/src/compiler/compile/css/gather_possible_values.ts b/src/compiler/compile/css/gather_possible_values.ts
index ea2ccd6fa8..85f2e032c8 100644
--- a/src/compiler/compile/css/gather_possible_values.ts
+++ b/src/compiler/compile/css/gather_possible_values.ts
@@ -1,4 +1,4 @@
-import { Node } from '../../interfaces';
+import { Node } from 'estree';
 
 export const UNKNOWN = {};
 
diff --git a/src/compiler/compile/css/interfaces.ts b/src/compiler/compile/css/interfaces.ts
new file mode 100644
index 0000000000..64dd8b3374
--- /dev/null
+++ b/src/compiler/compile/css/interfaces.ts
@@ -0,0 +1,6 @@
+export type CssNode = {
+	type: string;
+	start: number;
+	end: number;
+	[prop_name: string]: any;
+}
\ No newline at end of file
diff --git a/src/compiler/compile/nodes/EachBlock.ts b/src/compiler/compile/nodes/EachBlock.ts
index 225f3b441e..876646ea9c 100644
--- a/src/compiler/compile/nodes/EachBlock.ts
+++ b/src/compiler/compile/nodes/EachBlock.ts
@@ -1,49 +1,48 @@
-import Node from './shared/Node';
 import ElseBlock from './ElseBlock';
 import Expression from './shared/Expression';
 import map_children from './shared/map_children';
 import TemplateScope from './shared/TemplateScope';
 import AbstractBlock from './shared/AbstractBlock';
-import { Node as INode } from '../../interfaces';
-import { new_tail } from '../utils/tail';
 import Element from './Element';
+import { x } from 'code-red';
+import { Node, Identifier } from 'estree';
 
 interface Context {
-	key: INode;
+	key: Identifier;
 	name?: string;
-	tail: string;
+	modifier: (node: Node) => Node;
 }
 
-function unpack_destructuring(contexts: Context[], node: INode, tail: string) {
+function unpack_destructuring(contexts: Context[], node: Node, modifier: (node: Node) => Node) {
 	if (!node) return;
 
-	if (node.type === 'Identifier' || node.type === 'RestIdentifier') {
+	if (node.type === 'Identifier' || (node as any).type === 'RestIdentifier') { // TODO is this right? not RestElement?
 		contexts.push({
-			key: node,
-			tail
+			key: node as Identifier,
+			modifier
 		});
 	} else if (node.type === 'ArrayPattern') {
 		node.elements.forEach((element, i) => {
-			if (element && element.type === 'RestIdentifier') {
-				unpack_destructuring(contexts, element, `${tail}.slice(${i})`);
+			if (element && (element as any).type === 'RestIdentifier') {
+				unpack_destructuring(contexts, element, node => x`${node}.slice(${i})` as Node);
 			} else {
-				unpack_destructuring(contexts, element, `${tail}[${i}]`);
+				unpack_destructuring(contexts, element, node => x`${node}[${i}]` as Node);
 			}
 		});
 	} else if (node.type === 'ObjectPattern') {
 		const used_properties = [];
 
 		node.properties.forEach((property) => {
-			if (property.kind === 'rest') {
+			if ((property as any).kind === 'rest') { // TODO is this right?
 				unpack_destructuring(
 					contexts,
 					property.value,
-					`@object_without_properties(${tail}, ${JSON.stringify(used_properties)})`
+					node => x`@object_without_properties(${node}, ${JSON.stringify(used_properties)})` as Node
 				);
 			} else {
-				used_properties.push(property.key.name);
+				used_properties.push((property.key as Identifier).name);
 
-				unpack_destructuring(contexts, property.value,`${tail}.${property.key.name}`);
+				unpack_destructuring(contexts, property.value, node => x`${node}.${(property.key as Identifier).name}` as Node);
 			}
 		});
 	}
@@ -77,7 +76,7 @@ export default class EachBlock extends AbstractBlock {
 		this.scope = scope.child();
 
 		this.contexts = [];
-		unpack_destructuring(this.contexts, info.context, new_tail());
+		unpack_destructuring(this.contexts, info.context, node => node);
 
 		this.contexts.forEach(context => {
 			this.scope.add(context.key.name, this.expression.dependencies, this);
diff --git a/src/compiler/compile/nodes/EventHandler.ts b/src/compiler/compile/nodes/EventHandler.ts
index 0cd8000550..ecd19e5739 100644
--- a/src/compiler/compile/nodes/EventHandler.ts
+++ b/src/compiler/compile/nodes/EventHandler.ts
@@ -4,7 +4,7 @@ import Component from '../Component';
 import { b, x } from 'code-red';
 import Block from '../render_dom/Block';
 import { sanitize } from '../../utils/names';
-import { Identifier } from '../../interfaces';
+import { Identifier } from 'estree';
 
 export default class EventHandler extends Node {
 	type: 'EventHandler';
@@ -32,14 +32,16 @@ export default class EventHandler extends Node {
 			} else if (info.expression.type === 'Identifier') {
 				let node = component.node_for_declaration.get(info.expression.name);
 
-				if (node && node.type === 'VariableDeclaration') {
-					// for `const handleClick = () => {...}`, we want the [arrow] function expression node
-					const declarator = node.declarations.find(d => d.id.name === info.expression.name);
-					node = declarator && declarator.init;
-				}
+				if (node) {
+					if (node.type === 'VariableDeclaration') {
+						// for `const handleClick = () => {...}`, we want the [arrow] function expression node
+						const declarator = node.declarations.find(d => (d.id as Identifier).name === info.expression.name);
+						node = declarator && declarator.init;
+					}
 
-				if (node && /Function/.test(node.type) && node.params.length === 0) {
-					this.can_make_passive = true;
+					if ((node.type === 'FunctionExpression' || node.type === 'ArrowFunctionExpression') && node.params.length === 0) {
+						this.can_make_passive = true;
+					}
 				}
 			}
 		} else {
diff --git a/src/compiler/compile/nodes/Let.ts b/src/compiler/compile/nodes/Let.ts
index d855068c16..8401d277eb 100644
--- a/src/compiler/compile/nodes/Let.ts
+++ b/src/compiler/compile/nodes/Let.ts
@@ -20,7 +20,7 @@ export default class Let extends Node {
 			walk(info.expression, {
 				enter: node => {
 					if (!applicable.has(node.type)) {
-						component.error(node, {
+						component.error(node as any, {
 							code: 'invalid-let',
 							message: `let directive value must be an identifier or an object/array pattern`
 						});
diff --git a/src/compiler/compile/nodes/shared/Expression.ts b/src/compiler/compile/nodes/shared/Expression.ts
index 7b8ea6a925..00fa38c890 100644
--- a/src/compiler/compile/nodes/shared/Expression.ts
+++ b/src/compiler/compile/nodes/shared/Expression.ts
@@ -3,16 +3,16 @@ import { walk } from 'estree-walker';
 import is_reference from 'is-reference';
 import flatten_reference from '../../utils/flatten_reference';
 import { create_scopes, Scope, extract_names } from '../../utils/scope';
-import { Node } from '../../../interfaces';
 import { globals, sanitize } from '../../../utils/names';
 import Wrapper from '../../render_dom/wrappers/shared/Wrapper';
 import TemplateScope from './TemplateScope';
 import get_object from '../../utils/get_object';
 import Block from '../../render_dom/Block';
-import { INode } from '../interfaces';
 import is_dynamic from '../../render_dom/wrappers/shared/is_dynamic';
 import { x, b } from 'code-red';
 import { invalidate } from '../../utils/invalidate';
+import { Node, BinaryExpression, LogicalExpression, FunctionExpression } from 'estree';
+import { TemplateNode } from '../../../interfaces';
 
 const binary_operators: Record<string, number> = {
 	'**': 15,
@@ -53,8 +53,8 @@ const precedence: Record<string, (node?: Node) => number> = {
 	CallExpression: () => 19,
 	UpdateExpression: () => 17,
 	UnaryExpression: () => 16,
-	BinaryExpression: (node: Node) => binary_operators[node.operator],
-	LogicalExpression: (node: Node) => logical_operators[node.operator],
+	BinaryExpression: (node: BinaryExpression) => binary_operators[node.operator],
+	LogicalExpression: (node: LogicalExpression) => logical_operators[node.operator],
 	ConditionalExpression: () => 4,
 	AssignmentExpression: () => 3,
 	YieldExpression: () => 2,
@@ -62,14 +62,13 @@ const precedence: Record<string, (node?: Node) => number> = {
 	SequenceExpression: () => 0
 };
 
-type Owner = Wrapper | INode;
+type Owner = Wrapper | TemplateNode;
 
 export default class Expression {
 	type: 'Expression' = 'Expression';
 	component: Component;
 	owner: Owner;
 	node: any;
-	snippet: string;
 	references: Set<string>;
 	dependencies: Set<string> = new Set();
 	contextual_dependencies: Set<string> = new Set();
@@ -79,7 +78,7 @@ export default class Expression {
 	scope_map: WeakMap<Node, Scope>;
 
 	is_synthetic: boolean;
-	declarations: Node[] = [];
+	declarations: (Node | Node[])[] = [];
 	uses_context = false;
 
 	// todo: owner type
@@ -297,7 +296,7 @@ export default class Expression {
 					if (dependencies.size === 0 && contextual_dependencies.size === 0) {
 						// we can hoist this out of the component completely
 						component.fully_hoisted.push(declaration);
-						node.name = id;
+						// node.name = id;
 
 						this.replace(id as any);
 
@@ -312,7 +311,7 @@ export default class Expression {
 					else if (contextual_dependencies.size === 0) {
 						// function can be hoisted inside the component init
 						component.partly_hoisted.push(declaration);
-						node.name = id;
+						// node.name = id;
 
 						this.replace(x`#ctx.${id}` as any);
 
@@ -325,18 +324,21 @@ export default class Expression {
 
 					else {
 						// we need a combo block/init recipe
-						node.params.unshift({
+						(node as FunctionExpression).params.unshift({
 							type: 'ObjectPattern',
 							properties: Array.from(contextual_dependencies).map(name => ({
 								type: 'Property',
 								kind: 'init',
+								method: false,
+								shorthand: false,
+								computed: false,
 								key: { type: 'Identifier', name },
 								value: { type: 'Identifier', name }
 							}))
 						});
 
 						component.partly_hoisted.push(declaration);
-						node.name = id;
+						// node.name = id;
 
 						this.replace(id as any);
 
@@ -346,7 +348,7 @@ export default class Expression {
 							referenced: true
 						});
 
-						if (node.params.length > 0) {
+						if ((node as FunctionExpression).params.length > 0) {
 							declarations.push(b`
 								function ${id}(...args) {
 									return #ctx.${id}(#ctx, ...args);
diff --git a/src/compiler/compile/nodes/shared/map_children.ts b/src/compiler/compile/nodes/shared/map_children.ts
index 4072b176e5..dcdc52f86d 100644
--- a/src/compiler/compile/nodes/shared/map_children.ts
+++ b/src/compiler/compile/nodes/shared/map_children.ts
@@ -14,7 +14,7 @@ import Slot from '../Slot';
 import Text from '../Text';
 import Title from '../Title';
 import Window from '../Window';
-import { Node } from '../../../interfaces';
+import { TemplateNode } from '../../../interfaces';
 
 export type Children = ReturnType<typeof map_children>;
 
@@ -40,7 +40,7 @@ function get_constructor(type) {
 	}
 }
 
-export default function map_children(component, parent, scope, children: Node[]) {
+export default function map_children(component, parent, scope, children: TemplateNode[]) {
 	let last = null;
 	let ignores = [];
 
diff --git a/src/compiler/compile/render_dom/Block.ts b/src/compiler/compile/render_dom/Block.ts
index 610511ca4f..c149ca642d 100644
--- a/src/compiler/compile/render_dom/Block.ts
+++ b/src/compiler/compile/render_dom/Block.ts
@@ -1,7 +1,7 @@
 import Renderer from './Renderer';
 import Wrapper from './wrappers/shared/Wrapper';
 import { b, x } from 'code-red';
-import { Node, Identifier } from '../../interfaces';
+import { Node, Identifier } from 'estree';
 import { is_head } from './wrappers/shared/is_head';
 
 export interface BlockOptions {
@@ -14,9 +14,9 @@ export interface BlockOptions {
 	bindings?: Map<string, {
 		object: Identifier;
 		property: Identifier;
-		snippet: string;
+		snippet: Node;
 		store: string;
-		tail: string;
+		tail: Node;
 	}>;
 	dependencies?: Set<string>;
 }
@@ -38,24 +38,24 @@ export default class Block {
 	bindings: Map<string, {
 		object: Identifier;
 		property: Identifier;
-		snippet: string;
+		snippet: Node;
 		store: string;
-		tail: string
+		tail: Node;
 	}>;
 
 	chunks: {
-		init: Node[];
-		create: Node[];
-		claim: Node[];
-		hydrate: Node[];
-		mount: Node[];
-		measure: Node[];
-		fix: Node[];
-		animate: Node[];
-		intro: Node[];
-		update: Node[];
-		outro: Node[];
-		destroy: Node[];
+		init: (Node | Node[])[];
+		create: (Node | Node[])[];
+		claim: (Node | Node[])[];
+		hydrate: (Node | Node[])[];
+		mount: (Node | Node[])[];
+		measure: (Node | Node[])[];
+		fix: (Node | Node[])[];
+		animate: (Node | Node[])[];
+		intro: (Node | Node[])[];
+		update: (Node | Node[])[];
+		outro: (Node | Node[])[];
+		destroy: (Node | Node[])[];
 	};
 
 	event_listeners: Node[] = [];
diff --git a/src/compiler/compile/render_dom/Renderer.ts b/src/compiler/compile/render_dom/Renderer.ts
index 615db5e074..81fd4afe78 100644
--- a/src/compiler/compile/render_dom/Renderer.ts
+++ b/src/compiler/compile/render_dom/Renderer.ts
@@ -1,16 +1,17 @@
 import Block from './Block';
-import { CompileOptions, Node, Identifier } from '../../interfaces';
+import { CompileOptions } from '../../interfaces';
 import Component from '../Component';
 import FragmentWrapper from './wrappers/Fragment';
 import { x } from 'code-red';
+import { Node, Identifier } from 'estree';
 
 export default class Renderer {
 	component: Component; // TODO Maybe Renderer shouldn't know about Component?
 	options: CompileOptions;
 
-	blocks: Array<Block | string> = [];
+	blocks: Array<Block | Node | Node[]> = [];
 	readonly: Set<string> = new Set();
-	meta_bindings: Node[] = []; // initial values for e.g. window.innerWidth, if there's a <svelte:window> meta tag
+	meta_bindings: (Node | Node[])[] = []; // initial values for e.g. window.innerWidth, if there's a <svelte:window> meta tag
 	binding_groups: string[] = [];
 
 	block: Block;
@@ -49,14 +50,15 @@ export default class Renderer {
 			null
 		);
 
+		// TODO messy
 		this.blocks.forEach(block => {
-			if (typeof block !== 'string') {
+			if (block instanceof Block) {
 				block.assign_variable_names();
 			}
 		});
 
 		this.block.assign_variable_names();
 
-		this.fragment.render(this.block, null, x`nodes` as unknown as Identifier);
+		this.fragment.render(this.block, null, x`nodes` as Identifier);
 	}
 }
diff --git a/src/compiler/compile/render_dom/index.ts b/src/compiler/compile/render_dom/index.ts
index 8b4a3024da..fedbbbf463 100644
--- a/src/compiler/compile/render_dom/index.ts
+++ b/src/compiler/compile/render_dom/index.ts
@@ -8,6 +8,7 @@ import add_to_set from '../utils/add_to_set';
 import { extract_names } from '../utils/scope';
 import { invalidate } from '../utils/invalidate';
 import Block from './Block';
+import { ClassDeclaration, FunctionExpression } from 'estree';
 
 export default function dom(
 	component: Component,
@@ -322,26 +323,26 @@ export default function dom(
 		const fixed_reactive_declarations = []; // not really 'reactive' but whatever
 
 		component.reactive_declarations
-			.forEach(d => {
-				const dependencies = Array.from(d.dependencies);
-				const uses_props = !!dependencies.find(n => n === '$$props');
+			.forEach(_d => {
+				// const dependencies = Array.from(d.dependencies);
+				// const uses_props = !!dependencies.find(n => n === '$$props');
 
-				const condition = !uses_props && dependencies
-					.filter(n => {
-						const variable = component.var_lookup.get(n);
-						return variable && (variable.writable || variable.mutated);
-					})
-					.map(n => `$$dirty.${n}`).join(' || ');
+				// const condition = !uses_props && dependencies
+				// 	.filter(n => {
+				// 		const variable = component.var_lookup.get(n);
+				// 		return variable && (variable.writable || variable.mutated);
+				// 	})
+				// 	.map(n => `$$dirty.${n}`).join(' || ');
 
 				throw new Error(`bad`);
-				let snippet = `[✂${d.node.body.start}-${d.node.end}✂]`;
-				if (condition) snippet = `if (${condition}) { ${snippet} }`;
-
-				if (condition || uses_props) {
-					reactive_declarations.push(snippet);
-				} else {
-					fixed_reactive_declarations.push(snippet);
-				}
+				// let snippet = `[✂${d.node.body.start}-${d.node.end}✂]`;
+				// if (condition) snippet = `if (${condition}) { ${snippet} }`;
+
+				// if (condition || uses_props) {
+				// 	reactive_declarations.push(snippet);
+				// } else {
+				// 	fixed_reactive_declarations.push(snippet);
+				// }
 			});
 
 		const injected = Array.from(component.injected_reactive_declaration_vars).filter(name => {
@@ -396,7 +397,7 @@ export default function dom(
 
 				${unknown_props_check}
 
-				${component.slots.size && `let { $$slots = {}, $$scope } = $$props;`}
+				${component.slots.size && x`let { $$slots = {}, $$scope } = $$props;`}
 
 				${renderer.binding_groups.length > 0 && `const $$binding_groups = [${renderer.binding_groups.map(_ => `[]`).join(', ')}];`}
 
@@ -404,9 +405,9 @@ export default function dom(
 
 				${set && b`$$self.$set = ${set};`}
 
-				${capture_state && `$$self.$capture_state = ${capture_state};`}
+				${capture_state && x`$$self.$capture_state = ${capture_state};`}
 
-				${inject_state && `$$self.$inject_state = ${inject_state};`}
+				${inject_state && x`$$self.$inject_state = ${inject_state};`}
 
 				${injected.length && `let ${injected.join(', ')};`}
 
@@ -455,17 +456,18 @@ export default function dom(
 					}
 				}
 			}
-		`[0];
+		`[0] as ClassDeclaration;
 
 		if (props.length > 0) {
 			declaration.body.body.push({
 				type: 'MethodDefinition',
 				kind: 'get',
 				static: true,
+				computed: false,
 				key: { type: 'Identifier', name: 'observedAttributes' },
 				value: x`function() {
 					return [${props.map(prop => x`"${prop.export_name}"`)}];
-				}`
+				}` as FunctionExpression
 			})
 		}
 
@@ -495,7 +497,7 @@ export default function dom(
 					${dev_props_check}
 				}
 			}
-		`[0];
+		`[0] as ClassDeclaration;
 
 		declaration.body.body.push(...accessors);
 
diff --git a/src/compiler/compile/render_dom/wrappers/AwaitBlock.ts b/src/compiler/compile/render_dom/wrappers/AwaitBlock.ts
index 8c8b3d8ae0..2dff7a4a14 100644
--- a/src/compiler/compile/render_dom/wrappers/AwaitBlock.ts
+++ b/src/compiler/compile/render_dom/wrappers/AwaitBlock.ts
@@ -8,8 +8,8 @@ import FragmentWrapper from './Fragment';
 import PendingBlock from '../../nodes/PendingBlock';
 import ThenBlock from '../../nodes/ThenBlock';
 import CatchBlock from '../../nodes/CatchBlock';
-import { Identifier } from '../../../interfaces';
 import { changed } from './shared/changed';
+import { Identifier } from 'estree';
 
 class AwaitBlockBranch extends Wrapper {
 	node: PendingBlock | ThenBlock | CatchBlock;
@@ -234,7 +234,7 @@ export default class AwaitBlockWrapper extends Wrapper {
 		`);
 
 		[this.pending, this.then, this.catch].forEach(branch => {
-			branch.fragment.render(branch.block, null, x`nodes` as unknown as Identifier);
+			branch.fragment.render(branch.block, null, x`nodes` as Identifier);
 		});
 	}
 }
diff --git a/src/compiler/compile/render_dom/wrappers/Body.ts b/src/compiler/compile/render_dom/wrappers/Body.ts
index 42e5d562f1..dc1f561b1f 100644
--- a/src/compiler/compile/render_dom/wrappers/Body.ts
+++ b/src/compiler/compile/render_dom/wrappers/Body.ts
@@ -2,7 +2,7 @@ import Block from '../Block';
 import Wrapper from './shared/Wrapper';
 import { b } from 'code-red';
 import Body from '../../nodes/Body';
-import { Identifier } from '../../../interfaces';
+import { Identifier } from 'estree';
 
 export default class BodyWrapper extends Wrapper {
 	node: Body;
diff --git a/src/compiler/compile/render_dom/wrappers/DebugTag.ts b/src/compiler/compile/render_dom/wrappers/DebugTag.ts
index 2208732183..af8948698a 100644
--- a/src/compiler/compile/render_dom/wrappers/DebugTag.ts
+++ b/src/compiler/compile/render_dom/wrappers/DebugTag.ts
@@ -4,7 +4,7 @@ import Block from '../Block';
 import DebugTag from '../../nodes/DebugTag';
 // import add_to_set from '../../utils/add_to_set';
 import { b } from 'code-red';
-import { Identifier } from '../../../interfaces';
+import { Identifier } from 'estree';
 
 export default class DebugTagWrapper extends Wrapper {
 	node: DebugTag;
diff --git a/src/compiler/compile/render_dom/wrappers/EachBlock.ts b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
index db631a304e..629e20ff8d 100644
--- a/src/compiler/compile/render_dom/wrappers/EachBlock.ts
+++ b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
@@ -6,8 +6,7 @@ import EachBlock from '../../nodes/EachBlock';
 import FragmentWrapper from './Fragment';
 import { b, x } from 'code-red';
 import ElseBlock from '../../nodes/ElseBlock';
-import { attach_head } from '../../utils/tail';
-import { Identifier, Node } from '../../../interfaces';
+import { Identifier, Node } from 'estree';
 
 export class ElseBlockWrapper extends Wrapper {
 	node: ElseBlock;
@@ -61,7 +60,7 @@ export default class EachBlockWrapper extends Wrapper {
 		view_length: string;
 	}
 
-	context_props: string[];
+	context_props: (Node | Node[])[];
 	index_name: Identifier;
 
 	var: Identifier = { type: 'Identifier', name: 'each' };
@@ -141,9 +140,9 @@ export default class EachBlockWrapper extends Wrapper {
 			this.block.bindings.set(prop.key.name, {
 				object: this.vars.each_block_value,
 				property: this.index_name,
-				snippet: attach_head(`${this.vars.each_block_value}[${this.index_name}]`, prop.tail),
+				snippet: prop.modifier(x`${this.vars.each_block_value}[${this.index_name}]` as Node),
 				store,
-				tail: attach_head(`[${this.index_name}]`, prop.tail)
+				tail: prop.modifier(x`[${this.index_name}]` as Node)
 			});
 		});
 
@@ -189,7 +188,7 @@ export default class EachBlockWrapper extends Wrapper {
 			? !this.next.is_dom_node() :
 			!parent_node || !this.parent.is_dom_node();
 
-		this.context_props = this.node.contexts.map(prop => b`child_ctx.${prop.key.name} = ${attach_head('list[i]', prop.tail)};`);
+		this.context_props = this.node.contexts.map(prop => b`child_ctx.${prop.key.name} = ${prop.modifier(x`list[i]`)};`);
 
 		if (this.node.has_binding) this.context_props.push(b`child_ctx.${this.vars.each_block_value} = list;`);
 		if (this.node.has_binding || this.node.index) this.context_props.push(b`child_ctx.${this.index_name} = i;`);
@@ -243,7 +242,7 @@ export default class EachBlockWrapper extends Wrapper {
 				update_anchor_node as Identifier,
 				x`@empty()`,
 				parent_nodes && x`@empty()`,
-				parent_node as unknown as Node
+				parent_node
 			);
 		}
 
@@ -299,10 +298,10 @@ export default class EachBlockWrapper extends Wrapper {
 			`);
 		}
 
-		this.fragment.render(this.block, null, x`nodes` as unknown as Identifier);
+		this.fragment.render(this.block, null, x`nodes` as Identifier);
 
 		if (this.else) {
-			this.else.fragment.render(this.else.block, null, x`nodes` as unknown as Identifier);
+			this.else.fragment.render(this.else.block, null, x`nodes` as Identifier);
 		}
 	}
 
diff --git a/src/compiler/compile/render_dom/wrappers/Element/Binding.ts b/src/compiler/compile/render_dom/wrappers/Element/Binding.ts
index 19b6475aa5..ea1d18c061 100644
--- a/src/compiler/compile/render_dom/wrappers/Element/Binding.ts
+++ b/src/compiler/compile/render_dom/wrappers/Element/Binding.ts
@@ -3,12 +3,11 @@ import Binding from '../../../nodes/Binding';
 import ElementWrapper from '../Element';
 import get_object from '../../../utils/get_object';
 import Block from '../../Block';
-import Node from '../../../nodes/shared/Node';
 import Renderer from '../../Renderer';
 import flatten_reference from '../../../utils/flatten_reference';
 import EachBlock from '../../../nodes/EachBlock';
-import { Node as INode, Identifier } from '../../../../interfaces';
 import { changed } from '../shared/changed';
+import { Node, Identifier } from 'estree';
 
 export default class BindingWrapper {
 	node: Binding;
@@ -17,11 +16,11 @@ export default class BindingWrapper {
 	object: string;
 	handler: {
 		uses_context: boolean;
-		mutation: Node;
+		mutation: (Node | Node[]);
 		contextual_dependencies: Set<string>;
 		snippet?: Node;
 	};
-	snippet: INode;
+	snippet: Node;
 	is_readonly: boolean;
 	needs_lock: boolean;
 
@@ -157,17 +156,24 @@ export default class BindingWrapper {
 		}
 
 		if (update_dom) {
-			block.chunks.update.push(
-				update_conditions.length
-					? b`if (${update_conditions.join(' && ')}) {
+			if (update_conditions.length > 0) {
+				const condition = update_conditions.reduce((lhs, rhs) => x`${lhs} || ${rhs}`);
+
+				block.chunks.update.push(b`
+					if (${condition}) {
 						${update_dom}
-					}`
-					: update_dom
-			);
+					}
+				`);
+			} else {
+				block.chunks.update.push(update_dom);
+			}
 		}
 
 		if (this.node.name === 'innerHTML' || this.node.name === 'textContent') {
-			block.chunks.mount.push(b`if (${this.snippet} !== void 0) ${update_dom}`);
+			block.chunks.mount.push(b`
+				if (${this.snippet} !== void 0) {
+					${update_dom}
+				}`);
 		} else if (!/(currentTime|paused)/.test(this.node.name)) {
 			block.chunks.mount.push(update_dom);
 		}
@@ -228,8 +234,8 @@ function get_binding_group(renderer: Renderer, value: Node) {
 
 function mutate_store(store, value, tail) {
 	return tail
-		? `${store}.update($$value => ($$value${tail} = ${value}, $$value));`
-		: `${store}.set(${value});`;
+		? b`${store}.update($$value => ($$value${tail} = ${value}, $$value));`
+		: b`${store}.set(${value});`;
 }
 
 function get_event_handler(
@@ -240,7 +246,7 @@ function get_event_handler(
 	snippet: Node
 ): {
 	uses_context: boolean;
-	mutation: Node;
+	mutation: (Node | Node[]);
 	contextual_dependencies: Set<string>;
 	snippet?: Node;
 } {
@@ -260,14 +266,14 @@ function get_event_handler(
 
 		if (binding.store) {
 			store = binding.store;
-			tail = `${binding.tail}${tail}`;
+			tail = x`${binding.tail}.${tail}`;
 		}
 
 		return {
 			uses_context: true,
 			mutation: store
 				? mutate_store(store, value, tail)
-				: b`${snippet}${tail} = ${value};`,
+				: b`${snippet}.${tail} = ${value};`,
 			contextual_dependencies: new Set([object.name, property.name])
 		};
 	}
diff --git a/src/compiler/compile/render_dom/wrappers/Element/index.ts b/src/compiler/compile/render_dom/wrappers/Element/index.ts
index a3f05ecec8..30e1622a88 100644
--- a/src/compiler/compile/render_dom/wrappers/Element/index.ts
+++ b/src/compiler/compile/render_dom/wrappers/Element/index.ts
@@ -22,7 +22,7 @@ import { get_context_merger } from '../shared/get_context_merger';
 import bind_this from '../shared/bind_this';
 import { changed } from '../shared/changed';
 import { is_head } from '../shared/is_head';
-import { Identifier } from '../../../../interfaces';
+import { Identifier } from 'estree';
 
 const events = [
 	{
@@ -469,7 +469,7 @@ export default class ElementWrapper extends Wrapper {
 				} else {
 					block.chunks.init.push(b`
 						function ${handler}() {
-							${needs_lock && `${lock} = true;`}
+							${needs_lock && b`${lock} = true;`}
 							#ctx.${handler}.call(${this.var}, ${contextual_dependencies.size > 0 ? '#ctx' : null});
 						}
 					`);
@@ -508,8 +508,8 @@ export default class ElementWrapper extends Wrapper {
 			});
 
 			const some_initial_state_is_undefined = group.bindings
-				.map(binding => `${binding.snippet} === void 0`)
-				.join(' || ');
+				.map(binding => x`${binding.snippet} === void 0`)
+				.reduce((lhs, rhs) => x`${lhs} || ${rhs}`);
 
 			const should_initialise = (
 				this.node.name === 'select' ||
@@ -524,7 +524,7 @@ export default class ElementWrapper extends Wrapper {
 			);
 
 			if (should_initialise) {
-				const callback = has_local_function ? handler : `() => ${callee}.call(${this.var})`;
+				const callback = has_local_function ? handler : x`() => ${callee}.call(${this.var})`;
 				block.chunks.hydrate.push(
 					b`if (${some_initial_state_is_undefined}) @add_render_callback(${callback});`
 				);
diff --git a/src/compiler/compile/render_dom/wrappers/IfBlock.ts b/src/compiler/compile/render_dom/wrappers/IfBlock.ts
index 236f4c3e7b..595a04c324 100644
--- a/src/compiler/compile/render_dom/wrappers/IfBlock.ts
+++ b/src/compiler/compile/render_dom/wrappers/IfBlock.ts
@@ -8,9 +8,8 @@ import ElseBlock from '../../nodes/ElseBlock';
 import FragmentWrapper from './Fragment';
 import { b, x } from 'code-red';
 import { walk } from 'estree-walker';
-import { Identifier } from '../../../interfaces';
-import Node from '../../nodes/shared/Node';
 import { is_head } from './shared/is_head';
+import { Identifier, Node } from 'estree';
 
 function is_else_if(node: ElseBlock) {
 	return (
@@ -230,7 +229,7 @@ export default class IfBlockWrapper extends Wrapper {
 				anchor as Identifier,
 				x`@empty()`,
 				parent_nodes && x`@empty()`,
-				parent_node as unknown as Node
+				parent_node
 			);
 		}
 
diff --git a/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts b/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts
index 2241bfd96e..c07858314b 100644
--- a/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts
+++ b/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts
@@ -14,8 +14,8 @@ import EachBlock from '../../../nodes/EachBlock';
 import TemplateScope from '../../../nodes/shared/TemplateScope';
 import is_dynamic from '../shared/is_dynamic';
 import bind_this from '../shared/bind_this';
-import { Identifier } from '../../../../interfaces';
 import { changed } from '../shared/changed';
+import { Node, Identifier } from 'estree';
 
 export default class InlineComponentWrapper extends Wrapper {
 	var: Identifier;
@@ -116,8 +116,8 @@ export default class InlineComponentWrapper extends Wrapper {
 
 		const component_opts: any = x`{}`;
 
-		const statements: string[] = [];
-		const updates: string[] = [];
+		const statements: (Node | Node[])[] = [];
+		const updates: (Node | Node[])[] = [];
 
 		let props;
 		const name_changes = block.get_unique_name(`${name.name}_changes`);
@@ -301,7 +301,7 @@ export default class InlineComponentWrapper extends Wrapper {
 		}
 
 		if (non_let_dependencies.length > 0) {
-			updates.push(`if (${changed(non_let_dependencies)} ${name_changes}.$$scope = { changed: #changed, ctx: #ctx };`);
+			updates.push(b`if (${changed(non_let_dependencies)} ${name_changes}.$$scope = { changed: #changed, ctx: #ctx };`);
 		}
 
 		const munged_bindings = this.node.bindings.map(binding => {
@@ -339,7 +339,7 @@ export default class InlineComponentWrapper extends Wrapper {
 			const contextual_dependencies = Array.from(binding.expression.contextual_dependencies);
 			const dependencies = Array.from(binding.expression.dependencies);
 
-			let lhs = component.source.slice(binding.expression.node.start, binding.expression.node.end).trim();
+			let lhs = binding.expression.node;
 
 			if (binding.is_contextual && binding.expression.node.type === 'Identifier') {
 				// bind:x={y} — we can't just do `y = x`, we need to
diff --git a/src/compiler/compile/render_dom/wrappers/MustacheTag.ts b/src/compiler/compile/render_dom/wrappers/MustacheTag.ts
index aab21cd0e2..27364f5efb 100644
--- a/src/compiler/compile/render_dom/wrappers/MustacheTag.ts
+++ b/src/compiler/compile/render_dom/wrappers/MustacheTag.ts
@@ -4,8 +4,8 @@ import Tag from './shared/Tag';
 import Wrapper from './shared/Wrapper';
 import MustacheTag from '../../nodes/MustacheTag';
 import RawMustacheTag from '../../nodes/RawMustacheTag';
-import { Identifier, Node } from '../../../interfaces';
 import { x } from 'code-red';
+import { Identifier } from 'estree';
 
 export default class MustacheTagWrapper extends Tag {
 	var: Identifier = { type: 'Identifier', name: 't' };
@@ -25,7 +25,7 @@ export default class MustacheTagWrapper extends Tag {
 			this.var,
 			x`@text(${init})`,
 			parent_nodes && x`@claim_text(${parent_nodes}, ${init})`,
-			parent_node as unknown as Node
+			parent_node
 		);
 	}
 }
diff --git a/src/compiler/compile/render_dom/wrappers/RawMustacheTag.ts b/src/compiler/compile/render_dom/wrappers/RawMustacheTag.ts
index 5e9f15f7fd..74724535ac 100644
--- a/src/compiler/compile/render_dom/wrappers/RawMustacheTag.ts
+++ b/src/compiler/compile/render_dom/wrappers/RawMustacheTag.ts
@@ -5,8 +5,8 @@ import Tag from './shared/Tag';
 import Wrapper from './shared/Wrapper';
 import MustacheTag from '../../nodes/MustacheTag';
 import RawMustacheTag from '../../nodes/RawMustacheTag';
-import { Identifier, Node } from '../../../interfaces';
 import { is_head } from './shared/is_head';
+import { Identifier } from 'estree';
 
 export default class RawMustacheTagWrapper extends Tag {
 	var: Identifier = { type: 'Identifier', name: 'raw' };
@@ -56,7 +56,7 @@ export default class RawMustacheTagWrapper extends Tag {
 			block.chunks.mount.push(b`${html_tag}.m(${parent_node || '#target'}, ${parent_node ? null : 'anchor'});`);
 
 			if (needs_anchor) {
-				block.add_element(html_anchor, x`@empty()`, x`@empty()`, parent_node as unknown as Node);
+				block.add_element(html_anchor, x`@empty()`, x`@empty()`, parent_node);
 			}
 
 			if (!parent_node || in_head) {
diff --git a/src/compiler/compile/render_dom/wrappers/Slot.ts b/src/compiler/compile/render_dom/wrappers/Slot.ts
index ec78099062..c49ffa2a7d 100644
--- a/src/compiler/compile/render_dom/wrappers/Slot.ts
+++ b/src/compiler/compile/render_dom/wrappers/Slot.ts
@@ -10,7 +10,7 @@ import get_slot_data from '../../utils/get_slot_data';
 import { stringify_props } from '../../utils/stringify_props';
 import Expression from '../../nodes/shared/Expression';
 import is_dynamic from './shared/is_dynamic';
-import { Identifier } from '../../../interfaces';
+import { Identifier } from 'estree';
 
 export default class SlotWrapper extends Wrapper {
 	node: Slot;
diff --git a/src/compiler/compile/render_dom/wrappers/Text.ts b/src/compiler/compile/render_dom/wrappers/Text.ts
index 5bf139962b..5247eacdb6 100644
--- a/src/compiler/compile/render_dom/wrappers/Text.ts
+++ b/src/compiler/compile/render_dom/wrappers/Text.ts
@@ -2,9 +2,8 @@ import Renderer from '../Renderer';
 import Block from '../Block';
 import Text from '../../nodes/Text';
 import Wrapper from './shared/Wrapper';
-import { Identifier } from '../../../interfaces';
 import { x } from 'code-red';
-import Node from '../../nodes/shared/Node';
+import { Identifier } from 'estree';
 
 // Whitespace inside one of these elements will not result in
 // a whitespace node being created in any circumstances. (This
@@ -74,7 +73,7 @@ export default class TextWrapper extends Wrapper {
 			this.var,
 			use_space ? x`@space()` : x`@text("${this.data}")`,
 			parent_nodes && (use_space ? x`@claim_space(${parent_nodes})` : x`@claim_text(${parent_nodes}, "${this.data}")`),
-			parent_node as unknown as Node
+			parent_node as Identifier
 		);
 	}
 }
\ No newline at end of file
diff --git a/src/compiler/compile/render_dom/wrappers/Title.ts b/src/compiler/compile/render_dom/wrappers/Title.ts
index b1ae7a6d52..b7a0bcaa6b 100644
--- a/src/compiler/compile/render_dom/wrappers/Title.ts
+++ b/src/compiler/compile/render_dom/wrappers/Title.ts
@@ -6,7 +6,7 @@ import Title from '../../nodes/Title';
 import { stringify } from '../../utils/stringify';
 import add_to_set from '../../utils/add_to_set';
 import Text from '../../nodes/Text';
-import { Identifier } from '../../../interfaces';
+import { Identifier } from 'estree';
 
 export default class TitleWrapper extends Wrapper {
 	node: Title;
diff --git a/src/compiler/compile/render_dom/wrappers/Window.ts b/src/compiler/compile/render_dom/wrappers/Window.ts
index 9f8edd5682..7c4c351da4 100644
--- a/src/compiler/compile/render_dom/wrappers/Window.ts
+++ b/src/compiler/compile/render_dom/wrappers/Window.ts
@@ -5,9 +5,9 @@ import { b, x } from 'code-red';
 import add_event_handlers from './shared/add_event_handlers';
 import Window from '../../nodes/Window';
 import add_actions from './shared/add_actions';
-import { INode } from '../../nodes/interfaces';
 import { changed } from './shared/changed';
-import { Identifier } from '../../../interfaces';
+import { Identifier } from 'estree';
+import { TemplateNode } from '../../../interfaces';
 
 const associated_events = {
 	innerWidth: 'resize',
@@ -35,7 +35,7 @@ const readonly = new Set([
 export default class WindowWrapper extends Wrapper {
 	node: Window;
 
-	constructor(renderer: Renderer, block: Block, parent: Wrapper, node: INode) {
+	constructor(renderer: Renderer, block: Block, parent: Wrapper, node: TemplateNode) {
 		super(renderer, block, parent, node);
 	}
 
diff --git a/src/compiler/compile/render_dom/wrappers/shared/Tag.ts b/src/compiler/compile/render_dom/wrappers/shared/Tag.ts
index 38ba3f2411..5b0481af27 100644
--- a/src/compiler/compile/render_dom/wrappers/shared/Tag.ts
+++ b/src/compiler/compile/render_dom/wrappers/shared/Tag.ts
@@ -4,7 +4,7 @@ import Renderer from '../../Renderer';
 import Block from '../../Block';
 import MustacheTag from '../../../nodes/MustacheTag';
 import RawMustacheTag from '../../../nodes/RawMustacheTag';
-import { Node } from '../../../../interfaces';
+import { Node } from 'estree';
 
 export default class Tag extends Wrapper {
 	node: MustacheTag | RawMustacheTag;
@@ -18,7 +18,7 @@ export default class Tag extends Wrapper {
 
 	rename_this_method(
 		block: Block,
-		update: ((value: Node) => Node)
+		update: ((value: Node) => (Node | Node[]))
 	) {
 		const dependencies = this.node.expression.dynamic_dependencies();
 		const snippet = this.node.expression.manipulate(block);
diff --git a/src/compiler/compile/render_dom/wrappers/shared/Wrapper.ts b/src/compiler/compile/render_dom/wrappers/shared/Wrapper.ts
index de1475bfe5..5527ba3f7b 100644
--- a/src/compiler/compile/render_dom/wrappers/shared/Wrapper.ts
+++ b/src/compiler/compile/render_dom/wrappers/shared/Wrapper.ts
@@ -1,13 +1,13 @@
 import Renderer from '../../Renderer';
 import Block from '../../Block';
-import { INode } from '../../../nodes/interfaces';
-import { Identifier, Node } from '../../../../interfaces';
 import { x } from 'code-red';
+import { TemplateNode } from '../../../../interfaces';
+import { Identifier } from 'estree';
 
 export default class Wrapper {
 	renderer: Renderer;
 	parent: Wrapper;
-	node: INode;
+	node: TemplateNode;
 
 	prev: Wrapper | null;
 	next: Wrapper | null;
@@ -19,7 +19,7 @@ export default class Wrapper {
 		renderer: Renderer,
 		block: Block,
 		parent: Wrapper,
-		node: INode
+		node: TemplateNode
 	) {
 		this.node = node;
 
@@ -57,7 +57,7 @@ export default class Wrapper {
 				anchor,
 				x`@empty()`,
 				parent_nodes && x`@empty()`,
-				parent_node as unknown as Node
+				parent_node as Identifier
 			);
 		}
 
diff --git a/src/compiler/compile/render_dom/wrappers/shared/bind_this.ts b/src/compiler/compile/render_dom/wrappers/shared/bind_this.ts
index 63d280e87b..382fedf212 100644
--- a/src/compiler/compile/render_dom/wrappers/shared/bind_this.ts
+++ b/src/compiler/compile/render_dom/wrappers/shared/bind_this.ts
@@ -3,7 +3,7 @@ import { b, x } from 'code-red';
 import Component from '../../../Component';
 import Block from '../../Block';
 import Binding from '../../../nodes/Binding';
-import { Identifier } from '../../../../interfaces';
+import { Identifier } from 'estree';
 
 export default function bind_this(component: Component, block: Block, binding: Binding, variable: Identifier) {
 	const fn = component.get_unique_name(`${variable.name}_binding`);
@@ -81,7 +81,7 @@ export default function bind_this(component: Component, block: Block, binding: B
 		);
 
 		block.chunks.destroy.push(b`${unassign}();`);
-		return `${assign}();`;
+		return b`${assign}();`;
 	}
 
 	component.partly_hoisted.push(b`
diff --git a/src/compiler/compile/render_ssr/handlers/EachBlock.ts b/src/compiler/compile/render_ssr/handlers/EachBlock.ts
index d44c404603..ffe490922c 100644
--- a/src/compiler/compile/render_ssr/handlers/EachBlock.ts
+++ b/src/compiler/compile/render_ssr/handlers/EachBlock.ts
@@ -5,7 +5,7 @@ import EachBlock from '../../nodes/EachBlock';
 export default function(node: EachBlock, renderer: Renderer, options: RenderOptions) {
 	const snippet = snip(node.expression);
 
-	const { start, end } = node.context_node;
+	const { start, end } = node.context_node as any;
 
 	const ctx = node.index
 		? `([✂${start}-${end}✂], ${node.index})`
diff --git a/src/compiler/compile/render_ssr/index.ts b/src/compiler/compile/render_ssr/index.ts
index 3ab504bd77..81f8c719d3 100644
--- a/src/compiler/compile/render_ssr/index.ts
+++ b/src/compiler/compile/render_ssr/index.ts
@@ -3,8 +3,7 @@ import Component from '../Component';
 import { CompileOptions } from '../../interfaces';
 import { stringify } from '../utils/stringify';
 import Renderer from './Renderer';
-import { extract_names } from '../utils/scope';
-import { INode } from '../nodes/interfaces';
+import { INode as TemplateNode } from '../nodes/interfaces'; // TODO
 import Text from '../nodes/Text';
 
 export default function ssr(
@@ -65,33 +64,33 @@ export default function ssr(
 		})
 		: [];
 
-	const reactive_declarations = component.reactive_declarations.map(d => {
-		let snippet = `[✂${d.node.body.start}-${d.node.end}✂]`;
-
-		if (d.declaration) {
-			const declared = extract_names(d.declaration);
-			const injected = declared.filter(name => {
-				return name[0] !== '$' && component.var_lookup.get(name).injected;
-			});
-
-			const self_dependencies = injected.filter(name => d.dependencies.has(name));
-
-			if (injected.length) {
-				// in some cases we need to do `let foo; [expression]`, in
-				// others we can do `let [expression]`
-				const separate = (
-					self_dependencies.length > 0 ||
-					declared.length > injected.length ||
-					d.node.body.expression.type === 'ParenthesizedExpression'
-				);
-
-				snippet = separate
-					? `let ${injected.join(', ')}; ${snippet}`
-					: `let ${snippet}`;
-			}
-		}
-
-		return snippet;
+	const reactive_declarations = component.reactive_declarations.map(_d => {
+		throw new Error('TODO');
+		// let snippet = `[✂${d.node.body.start}-${d.node.end}✂]`;
+
+		// if (d.declaration) {
+		// 	const declared = extract_names(d.declaration);
+		// 	const injected = declared.filter(name => {
+		// 		return name[0] !== '$' && component.var_lookup.get(name).injected;
+		// 	});
+
+		// 	const self_dependencies = injected.filter(name => d.dependencies.has(name));
+
+		// 	if (injected.length) {
+		// 		// in some cases we need to do `let foo; [expression]`, in
+		// 		// others we can do `let [expression]`
+		// 		const separate = (
+		// 			self_dependencies.length > 0 ||
+		// 			declared.length > injected.length
+		// 		);
+
+		// 		snippet = separate
+		// 			? `let ${injected.join(', ')}; ${snippet}`
+		// 			: `let ${snippet}`;
+		// 	}
+		// }
+
+		// return snippet;
 	});
 
 	const main = renderer.has_bindings
@@ -153,7 +152,7 @@ export default function ssr(
 	`;
 }
 
-function trim(nodes: INode[]) {
+function trim(nodes: TemplateNode[]) {
 	let start = 0;
 	for (; start < nodes.length; start += 1) {
 		const node = nodes[start] as Text;
diff --git a/src/compiler/compile/utils/flatten_reference.ts b/src/compiler/compile/utils/flatten_reference.ts
index 7b814d5e19..1a1d13d0a6 100644
--- a/src/compiler/compile/utils/flatten_reference.ts
+++ b/src/compiler/compile/utils/flatten_reference.ts
@@ -1,7 +1,11 @@
-import { Node } from '../../interfaces';
+import { Node, Identifier } from 'estree';
 
 export default function flatten_reference(node: Node) {
-	if (node.type === 'Expression') throw new Error('bad');
+	// TODO temporary (#3539)
+	if ((node as any).type === 'Expression') {
+		throw new Error('bad');
+	}
+
 	const nodes = [];
 	const parts = [];
 
@@ -9,7 +13,7 @@ export default function flatten_reference(node: Node) {
 		nodes.unshift(node.property);
 
 		if (!node.computed) {
-			parts.unshift(node.property.name);
+			parts.unshift((node.property as Identifier).name);
 		}
 
 		node = node.object;
@@ -21,7 +25,7 @@ export default function flatten_reference(node: Node) {
 
 	nodes.unshift(node);
 
-	if (!node.computed) {
+	if (!(node as any).computed) {
 		parts.unshift(name);
 	}
 
diff --git a/src/compiler/compile/utils/get_object.ts b/src/compiler/compile/utils/get_object.ts
index 641ebdcb9c..863bfb0d61 100644
--- a/src/compiler/compile/utils/get_object.ts
+++ b/src/compiler/compile/utils/get_object.ts
@@ -1,8 +1,6 @@
-import { Node } from '../../interfaces';
-import unwrap_parens from './unwrap_parens';
+import { Node, Identifier } from 'estree';
 
-export default function get_object(node: Node) {
-	node = unwrap_parens(node);
+export default function get_object(node: Node): Identifier {
 	while (node.type === 'MemberExpression') node = node.object;
-	return node;
+	return node as Identifier;
 }
diff --git a/src/compiler/compile/utils/invalidate.ts b/src/compiler/compile/utils/invalidate.ts
index b21c9c7816..e41e1e3b56 100644
--- a/src/compiler/compile/utils/invalidate.ts
+++ b/src/compiler/compile/utils/invalidate.ts
@@ -1,8 +1,8 @@
 import Component from '../Component';
-import { Node } from '../../interfaces';
 import { nodes_match } from '../../utils/nodes_match';
 import { Scope } from './scope';
 import { x } from 'code-red';
+import { Node } from 'estree';
 
 export function invalidate(component: Component, scope: Scope, node: Node, names: Set<string>) {
 	const [head, ...tail] = Array.from(names).filter(name => {
@@ -27,7 +27,7 @@ export function invalidate(component: Component, scope: Scope, node: Node, names
 	if (head) {
 		component.has_reactive_assignments = true;
 
-		if (node.operator === '=' && nodes_match(node.left, node.right) && tail.length === 0) {
+		if (node.type === 'AssignmentExpression' && node.operator === '=' && nodes_match(node.left, node.right) && tail.length === 0) {
 			return component.invalidate(head);
 		} else {
 
diff --git a/src/compiler/compile/utils/scope.ts b/src/compiler/compile/utils/scope.ts
index 0255ac9419..239438ba9c 100644
--- a/src/compiler/compile/utils/scope.ts
+++ b/src/compiler/compile/utils/scope.ts
@@ -1,9 +1,9 @@
 import { walk } from 'estree-walker';
 import is_reference from 'is-reference';
-import { Node } from '../../interfaces';
-import { Node as ESTreeNode } from 'estree';
+import { Node, VariableDeclaration, ClassDeclaration, VariableDeclarator, ObjectPattern, Property, RestElement, ArrayPattern, Identifier } from 'estree';
 import get_object from './get_object';
 
+// TODO replace this with periscopic?
 export function create_scopes(expression: Node) {
 	const map = new WeakMap();
 
@@ -16,7 +16,7 @@ export function create_scopes(expression: Node) {
 				node.specifiers.forEach(specifier => {
 					scope.declarations.set(specifier.local.name, specifier);
 				});
-			} else if (/Function/.test(node.type)) {
+			} else if (node.type === 'FunctionDeclaration' || node.type === 'FunctionExpression' || node.type === 'ArrowFunctionExpression') {
 				if (node.type === 'FunctionDeclaration') {
 					scope.declarations.set(node.id.name, node);
 					scope = new Scope(scope, false);
@@ -24,7 +24,9 @@ export function create_scopes(expression: Node) {
 				} else {
 					scope = new Scope(scope, false);
 					map.set(node, scope);
-					if (node.id) scope.declarations.set(node.id.name, node);
+					if (node.type === 'FunctionExpression' && node.id) {
+						scope.declarations.set(node.id.name, node);
+					}
 				}
 
 				node.params.forEach((param) => {
@@ -38,7 +40,7 @@ export function create_scopes(expression: Node) {
 			} else if (node.type === 'BlockStatement') {
 				scope = new Scope(scope, true);
 				map.set(node, scope);
-			} else if (/(Class|Variable)Declaration/.test(node.type)) {
+			} else if (node.type === 'ClassDeclaration' || node.type === 'VariableDeclaration') {
 				scope.add_declaration(node);
 			} else if (node.type === 'CatchClause') {
 				scope = new Scope(scope, true);
@@ -47,7 +49,7 @@ export function create_scopes(expression: Node) {
 				extract_names(node.param).forEach(name => {
 					scope.declarations.set(name, node.param);
 				});
-			} else if (node.type === 'Identifier' && is_reference(node as ESTreeNode, parent as ESTreeNode)) {
+			} else if (node.type === 'Identifier' && is_reference(node as Node, parent as Node)) {
 				if (!scope.has(node.name) && !globals.has(node.name)) {
 					globals.set(node.name, node);
 				}
@@ -80,16 +82,18 @@ export class Scope {
 		this.block = block;
 	}
 
-	add_declaration(node: Node) {
-		if (node.kind === 'var' && this.block && this.parent) {
-			this.parent.add_declaration(node);
-		} else if (node.type === 'VariableDeclaration') {
-			node.declarations.forEach((declarator: Node) => {
-				extract_names(declarator.id).forEach(name => {
-					this.declarations.set(name, node);
-					if (declarator.init) this.initialised_declarations.add(name);
+	add_declaration(node: VariableDeclaration | ClassDeclaration) {
+		if (node.type === 'VariableDeclaration') {
+			if (node.kind === 'var' && this.block && this.parent) {
+				this.parent.add_declaration(node);
+			} else {
+				node.declarations.forEach((declarator: VariableDeclarator) => {
+					extract_names(declarator.id).forEach(name => {
+						this.declarations.set(name, node);
+						if (declarator.init) this.initialised_declarations.add(name);
+					});
 				});
-			});
+			}
 		} else {
 			this.declarations.set(node.id.name, node);
 		}
@@ -107,12 +111,12 @@ export class Scope {
 	}
 }
 
-export function extract_names(param: Node) {
-	return extract_identifiers(param).map(node => node.name);
+export function extract_names(param: Node): string[] {
+	return extract_identifiers(param).map((node: any) => node.name);
 }
 
-export function extract_identifiers(param: Node) {
-	const nodes: Node[] = [];
+export function extract_identifiers(param: Node): Identifier[] {
+	const nodes: Identifier[] = [];
 	extractors[param.type] && extractors[param.type](nodes, param);
 	return nodes;
 }
@@ -126,8 +130,8 @@ const extractors = {
 		nodes.push(get_object(param));
 	},
 
-	ObjectPattern(nodes: Node[], param: Node) {
-		param.properties.forEach((prop: Node) => {
+	ObjectPattern(nodes: Node[], param: ObjectPattern) {
+		param.properties.forEach((prop: Property | RestElement) => {
 			if (prop.type === 'RestElement') {
 				nodes.push(prop.argument);
 			} else {
@@ -136,17 +140,17 @@ const extractors = {
 		});
 	},
 
-	ArrayPattern(nodes: Node[], param: Node) {
+	ArrayPattern(nodes: Node[], param: ArrayPattern) {
 		param.elements.forEach((element: Node) => {
 			if (element) extractors[element.type](nodes, element);
 		});
 	},
 
-	RestElement(nodes: Node[], param: Node) {
+	RestElement(nodes: Node[], param: any) {
 		extractors[param.argument.type](nodes, param.argument);
 	},
 
-	AssignmentPattern(nodes: Node[], param: Node) {
+	AssignmentPattern(nodes: Node[], param: any) {
 		extractors[param.left.type](nodes, param.left);
 	}
 };
diff --git a/src/compiler/compile/utils/tail.ts b/src/compiler/compile/utils/tail.ts
deleted file mode 100644
index 87a3daf4fe..0000000000
--- a/src/compiler/compile/utils/tail.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-export function new_tail(): string {
-	return '%%tail_head%%';
-}
-
-export function attach_head(head: string, tail: string): string {
-	return tail.replace('%%tail_head%%', head);
-}
diff --git a/src/compiler/compile/utils/unwrap_parens.ts b/src/compiler/compile/utils/unwrap_parens.ts
deleted file mode 100644
index 71a03b2b69..0000000000
--- a/src/compiler/compile/utils/unwrap_parens.ts
+++ /dev/null
@@ -1,6 +0,0 @@
-import { Node } from '../../interfaces';
-
-export default function unwrap_parens(node: Node) {
-	while (node.type === 'ParenthesizedExpression') node = node.expression;
-	return node;
-}
\ No newline at end of file
diff --git a/src/compiler/interfaces.ts b/src/compiler/interfaces.ts
index dd73e53e4a..5d3acda67b 100644
--- a/src/compiler/interfaces.ts
+++ b/src/compiler/interfaces.ts
@@ -1,16 +1,18 @@
-export interface Identifier {
-	type: 'Identifier';
-	name: string;
-}
+import { Node, Program } from "estree";
 
 interface BaseNode {
 	start: number;
 	end: number;
 	type: string;
-	children?: Node[];
+	children?: TemplateNode[];
 	[prop_name: string]: any;
 }
 
+export interface Fragment extends BaseNode {
+	type: 'Fragment';
+	children: TemplateNode[];
+}
+
 export interface Text extends BaseNode {
 	type: 'Text';
 	data: string;
@@ -32,7 +34,7 @@ export type DirectiveType = 'Action'
 
 interface BaseDirective extends BaseNode {
 	type: DirectiveType;
-	expression: null|Node;
+	expression: null | Node;
 	name: string;
 	modifiers: string[];
 }
@@ -45,7 +47,7 @@ export interface Transition extends BaseDirective{
 
 export type Directive = BaseDirective | Transition;
 
-export type Node = Text
+export type TemplateNode = Text
 | MustacheTag
 | BaseNode
 | Directive
@@ -64,11 +66,28 @@ export interface Parser {
 	meta_tags: {};
 }
 
+export interface Script extends BaseNode {
+	type: 'Script',
+	context: string;
+	content: Program;
+}
+
+export interface Style extends BaseNode {
+	type: 'Style';
+	attributes: any[]; // TODO
+	children: any[]; // TODO add CSS node types
+	content: {
+		start: number;
+		end: number;
+		styles: string;
+	}
+}
+
 export interface Ast {
-	html: Node;
-	css: Node;
-	instance: Node;
-	module: Node;
+	html: TemplateNode;
+	css: Style;
+	instance: Script;
+	module: Script;
 }
 
 export interface Warning {
diff --git a/src/compiler/parse/index.ts b/src/compiler/parse/index.ts
index 2110df7280..5416038a53 100644
--- a/src/compiler/parse/index.ts
+++ b/src/compiler/parse/index.ts
@@ -3,7 +3,7 @@ import fragment from './state/fragment';
 import { whitespace } from '../utils/patterns';
 import { reserved } from '../utils/names';
 import full_char_code_at from '../utils/full_char_code_at';
-import { Node, Ast, ParserOptions } from '../interfaces';
+import { TemplateNode, Ast, ParserOptions, Fragment, Style, Script } from '../interfaces';
 import error from '../utils/error';
 
 type ParserState = (parser: Parser) => (ParserState | void);
@@ -14,11 +14,11 @@ export class Parser {
 	readonly customElement: boolean;
 
 	index = 0;
-	stack: Node[] = [];
+	stack: TemplateNode[] = [];
 
-	html: Node;
-	css: Node[] = [];
-	js: Node[] = [];
+	html: Fragment;
+	css: Style[] = [];
+	js: Script[] = [];
 	meta_tags = {};
 
 	constructor(template: string, options: ParserOptions) {
@@ -207,7 +207,7 @@ export default function parse(
 ): Ast {
 	const parser = new Parser(template, options);
 
-	// TODO we way want to allow multiple <style> tags —
+	// TODO we may want to allow multiple <style> tags —
 	// one scoped, one global. for now, only allow one
 	if (parser.css.length > 1) {
 		parser.error({
diff --git a/src/compiler/parse/read/script.ts b/src/compiler/parse/read/script.ts
index 59e4451dca..ed427d6551 100644
--- a/src/compiler/parse/read/script.ts
+++ b/src/compiler/parse/read/script.ts
@@ -1,11 +1,12 @@
 import * as acorn from '../acorn';
 import repeat from '../../utils/repeat';
 import { Parser } from '../index';
-import { Node } from '../../interfaces';
+import { Script } from '../../interfaces';
+import { Node, Program } from 'estree';
 
 const script_closing_tag = '</script>';
 
-function get_context(parser: Parser, attributes: Node[], start: number) {
+function get_context(parser: Parser, attributes: any[], start: number): string {
 	const context = attributes.find(attribute => attribute.name === 'context');
 	if (!context) return 'default';
 
@@ -28,7 +29,7 @@ function get_context(parser: Parser, attributes: Node[], start: number) {
 	return value;
 }
 
-export default function read_script(parser: Parser, start: number, attributes: Node[]) {
+export default function read_script(parser: Parser, start: number, attributes: Node[]) : Script {
 	const script_start = parser.index;
 	const script_end = parser.template.indexOf(script_closing_tag, script_start);
 
@@ -41,7 +42,7 @@ export default function read_script(parser: Parser, start: number, attributes: N
 		repeat(' ', script_start) + parser.template.slice(script_start, script_end);
 	parser.index = script_end + script_closing_tag.length;
 
-	let ast;
+	let ast: Program;
 
 	try {
 		ast = acorn.parse(source);
@@ -49,8 +50,11 @@ export default function read_script(parser: Parser, start: number, attributes: N
 		parser.acorn_error(err);
 	}
 
-	ast.start = script_start;
+	// TODO is this necessary?
+	(ast as any).start = script_start;
+
 	return {
+		type: 'Script',
 		start,
 		end: parser.index,
 		context: get_context(parser, attributes, start),
diff --git a/src/compiler/parse/read/style.ts b/src/compiler/parse/read/style.ts
index a14356e05b..4a16475d6b 100644
--- a/src/compiler/parse/read/style.ts
+++ b/src/compiler/parse/read/style.ts
@@ -1,9 +1,10 @@
 import parse from 'css-tree/lib/parser/index.js';
 import { walk } from 'estree-walker';
 import { Parser } from '../index';
-import { Node } from '../../interfaces';
+import { Node } from 'estree';
+import { Style } from '../../interfaces';
 
-export default function read_style(parser: Parser, start: number, attributes: Node[]) {
+export default function read_style(parser: Parser, start: number, attributes: Node[]): Style {
 	const content_start = parser.index;
 	const styles = parser.read_until(/<\/style>/);
 	const content_end = parser.index;
@@ -30,7 +31,7 @@ export default function read_style(parser: Parser, start: number, attributes: No
 
 	// tidy up AST
 	walk(ast, {
-		enter: (node: Node) => {
+		enter: (node: any) => { // `any` because this isn't an ESTree node
 			// replace `ref:a` nodes
 			if (node.type === 'Selector') {
 				for (let i = 0; i < node.children.length; i += 1) {
@@ -58,6 +59,7 @@ export default function read_style(parser: Parser, start: number, attributes: No
 	const end = parser.index;
 
 	return {
+		type: 'Style',
 		start,
 		end,
 		attributes,
@@ -65,12 +67,12 @@ export default function read_style(parser: Parser, start: number, attributes: No
 		content: {
 			start: content_start,
 			end: content_end,
-			styles,
-		},
+			styles
+		}
 	};
 }
 
-function is_ref_selector(a: Node, b: Node) {
+function is_ref_selector(a: any, b: any) { // TODO add CSS node types
 	if (!b) return false;
 
 	return (
diff --git a/src/compiler/parse/state/mustache.ts b/src/compiler/parse/state/mustache.ts
index 8de35cee48..4a1578ada5 100644
--- a/src/compiler/parse/state/mustache.ts
+++ b/src/compiler/parse/state/mustache.ts
@@ -4,9 +4,9 @@ import { closing_tag_omitted } from '../utils/html';
 import { whitespace } from '../../utils/patterns';
 import { trim_start, trim_end } from '../../utils/trim';
 import { Parser } from '../index';
-import { Node } from '../../interfaces';
+import { TemplateNode } from '../../interfaces';
 
-function trim_whitespace(block: Node, trim_before: boolean, trim_after: boolean) {
+function trim_whitespace(block: TemplateNode, trim_before: boolean, trim_after: boolean) {
 	if (!block.children || block.children.length === 0) return; // AwaitBlock
 
 	const first_child = block.children[0];
@@ -175,7 +175,7 @@ export default function mustache(parser: Parser) {
 				parser.eat('}', true);
 			}
 
-			const then_block: Node = {
+			const then_block: TemplateNode = {
 				start,
 				end: null,
 				type: 'ThenBlock',
@@ -200,7 +200,7 @@ export default function mustache(parser: Parser) {
 				parser.eat('}', true);
 			}
 
-			const catch_block: Node = {
+			const catch_block: TemplateNode = {
 				start,
 				end: null,
 				type: 'CatchBlock',
@@ -232,7 +232,7 @@ export default function mustache(parser: Parser) {
 
 		const expression = read_expression(parser);
 
-		const block: Node = type === 'AwaitBlock' ?
+		const block: TemplateNode = type === 'AwaitBlock' ?
 			{
 				start,
 				end: null,
diff --git a/src/compiler/parse/state/tag.ts b/src/compiler/parse/state/tag.ts
index 21a7b3caea..6b187d141b 100644
--- a/src/compiler/parse/state/tag.ts
+++ b/src/compiler/parse/state/tag.ts
@@ -4,7 +4,7 @@ import read_style from '../read/style';
 import { decode_character_references, closing_tag_omitted } from '../utils/html';
 import { is_void } from '../../utils/names';
 import { Parser } from '../index';
-import { Directive, DirectiveType, Node, Text } from '../../interfaces';
+import { Directive, DirectiveType, TemplateNode, Text } from '../../interfaces';
 import fuzzymatch from '../../utils/fuzzymatch';
 import list from '../../utils/list';
 
@@ -112,7 +112,7 @@ export default function tag(parser: Parser) {
 			: name === 'title' && parent_is_head(parser.stack) ? 'Title'
 				: name === 'slot' && !parser.customElement ? 'Slot' : 'Element';
 
-	const element: Node = {
+	const element: TemplateNode = {
 		start,
 		end: null, // filled in later
 		type,
@@ -406,7 +406,7 @@ function read_attribute(parser: Parser, unique_names: Set<string>) {
 				end: directive.end,
 				type: 'Identifier',
 				name: directive.name
-			};
+			} as any;
 		}
 
 		return directive;
@@ -447,7 +447,7 @@ function read_attribute_value(parser: Parser) {
 	return value;
 }
 
-function read_sequence(parser: Parser, done: () => boolean): Node[] {
+function read_sequence(parser: Parser, done: () => boolean): TemplateNode[] {
 	let current_chunk: Text = {
 		start: parser.index,
 		end: null,
@@ -464,7 +464,7 @@ function read_sequence(parser: Parser, done: () => boolean): Node[] {
 		}
 	}
 
-	const chunks: Node[] = [];
+	const chunks: TemplateNode[] = [];
 
 	while (parser.index < parser.template.length) {
 		const index = parser.index;