52 changed files with 3283 additions and 3639 deletions
--- a/.editorconfig
+++ b/.editorconfig
@ -6,3 +6,4 @@ indent_size = 4
 charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
+end_of_line = lf
--- a/.eslintignore
+++ b/.eslintignore
@ -1 +0,0 @@
-node_modules
--- a/.eslintrc
+++ b/.eslintrc
@ -1,11 +0,0 @@
-{
-    "root": true,
-    "parser": "@typescript-eslint/parser",
-    "plugins": ["@typescript-eslint", "prettier"],
-    "extends": [
-        "eslint:recommended",
-        "plugin:@typescript-eslint/eslint-recommended",
-        "plugin:@typescript-eslint/recommended",
-        "plugin:prettier/recommended"
-    ]
-}
--- a/.forgejo/workflows/ci.yml
+++ b/.forgejo/workflows/ci.yml
@ -0,0 +1,38 @@
+name: CI
+
+on:
+    push:
+        branches: [main]
+    pull_request:
+        branches: [main]
+    workflow_dispatch:
+
+jobs:
+    check:
+        runs-on: node-24
+        steps:
+            - uses: https://code.forgejo.org/actions/checkout@v4
+            - name: Cache npm dependencies
+              uses: https://code.forgejo.org/actions/cache@v4
+              with:
+                path: ~/.npm
+                key: node-24-${{ hashFiles('**/package-lock.json') }}
+            - run: npm ci
+            - run: npm run check
+
+    build:
+        needs: check
+        strategy:
+            matrix:
+                node: [22, 24]
+        runs-on: node-${{ matrix.node }}
+        steps:
+            - uses: https://code.forgejo.org/actions/checkout@v4
+            - name: Cache npm dependencies
+              uses: https://code.forgejo.org/actions/cache@v4
+              with:
+                path: ~/.npm
+                key: node-${{ matrix.node }}-${{ hashFiles('**/package-lock.json') }}
+            - run: npm ci
+            - run: npm run build
+            - run: npm test
--- a/.gitattributes
+++ b/.gitattributes
@ -0,0 +1,2 @@
+# Ensure that git uses lf line-endings for text files.
+* text=auto eol=lf
--- a/.gitignore
+++ b/.gitignore
@ -1,3 +1,4 @@
 /dist
+/.temp
 public/
 node_modules/
--- a/.nvmrc
+++ b/.nvmrc
@ -1 +1 @@
-lts/erbium
+18
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -0,0 +1,52 @@
+# Changelog
+
+## [0.2.0](https://github.com/websnacksjs/websnacks/releases/tag/v0.2.0) (2021-02-28)
+
+### Features
+
+-   add dangerouslySetInnerHTML attr ([#15](https://github.com/websnacksjs/websnacks/issues/15), [3f356dd](https://github.com/websnacksjs/websnacks/commit/3f356ddfeeb38e8a60c32d26c3e9e8715d0246c3))
+
+### Misc
+
+-   **BREAKING CHANGE** update node-watch optional dep to major v0.7.1
+
+## [0.1.5](https://github.com/websnacksjs/websnacks/releases/tag/v0.1.5) (2020-06-14)
+
+### Bugfixes
+
+-   stack size exceed error on purging module cache ([32eee9b](https://github.com/websnacksjs/websnacks/commit/32eee9b2e04475452905e3478f0fa2a21ad3ccf4))
+
+## [0.1.4](https://github.com/websnacksjs/websnacks/releases/tag/v0.1.4) (2020-06-10)
+
+### Bugfixes
+
+-   dev cmd didn't watch files due to import mangling ([4e44d83](https://github.com/websnacksjs/websnacks/commit/4e44d8369451e19af616a8c03c2ff7f4065b3f50))
+-   dont require config file ([5520bb3](https://github.com/websnacksjs/websnacks/commit/5520bb3571189726df73a2945d9a6e7f5671e7ff))
+
+## [0.1.3](https://github.com/websnacksjs/websnacks/releases/tag/v0.1.3) (2020-06-04)
+
+### Features
+
+-   provide Fragment component ([#9](https://github.com/websnacksjs/websnacks/issues/9), [f1aca35](https://github.com/websnacksjs/websnacks/commit/f1aca350ed7e63e277fae7f9cc01039a29442bcb))
+
+## [0.1.2](https://github.com/websnacksjs/websnacks/releases/tag/v0.1.2) (2020-06-03)
+
+### Bugfixes
+
+-   type signature of Component too narrow ([7fd8fe9](https://github.com/websnacksjs/websnacks/commit/7fd8fe9be855c5eb02f0d3b291fc6403a4c636a2))
+
+## [0.1.1](https://github.com/websnacksjs/websnacks/releases/tag/v0.1.1) (2020-06-03)
+
+### Features
+
+-   support rendering array elements ([#7](https://github.com/websnacksjs/websnacks/issues/7)) ([f5a83e7](https://github.com/websnacksjs/websnacks/commit/f5a83e7b7f618a67b37f74863ef3600a771383f4))
+
+### Bugfixes
+
+-   output declarations, sourcemaps again ([5568777](https://github.com/websnacksjs/websnacks/commit/5568777f6af0b1a591f7c177c965f91540ff8167))
+-   target es2018 to support node10+ ([e774fc1](https://github.com/websnacksjs/websnacks/commit/e774fc1b6c7e87d58ca4544cad8c293d04dae470))
+-   support number elements in jsx templates ([#5](https://github.com/websnacksjs/websnacks/issues/5)) ([83c0c91](https://github.com/websnacksjs/websnacks/commit/83c0c91bcfc3c219793fa05da84c9cde0fbf6c85))
+
+## [0.1.0](https://github.com/websnacksjs/websnacks/releases/tag/v0.1.0) (2020-05-26)
+
+**Note:** Initial release.
--- a/README.md
+++ b/README.md
@ -1,5 +1,10 @@
 # websnacks: Minimal Dependency Server-Side JSX for Static Sites

+[![NPM release](https://badges.git.theinnerlimit.ch/npm/v/@websnacksjs/websnacks?style=flat-square)](https://www.npmjs.com/package/@websnacksjs/websnacks "NPM release")
+[![NPM](https://badges.git.theinnerlimit.ch/npm/l/@websnacksjs/websnacks?style=flat-square)](https://www.mozilla.org/en-US/MPL/2.0/FAQ/ "License info")
+[![Build status](https://git.theinnerlimit.ch/websnacksjs/websnacks/badges/workflows/ci.yml/badge.svg?event=push&label=ci&style=flat-square)](https://git.theinnerlimit.ch/websnacksjs/websnacks/actions?workflow=ci.yml "CI status for main branch")
+![Dependency status](https://badges.git.theinnerlimit.ch/librariesio/release/npm/%40websnacksjs%2Fwebsnacks?style=flat-square)
+
 Develop fully static websites using typesafe JSX templates on the server without the complex build system and dependency management of server-side rendered React frameworks.

 ## Goals
--- a/biome.json
+++ b/biome.json
@ -0,0 +1,41 @@
+{
+	"$schema": "https://biomejs.dev/schemas/2.4.14/schema.json",
+	"files": {
+		"includes": ["**", "!dist", "!node_modules", "!.temp"]
+	},
+	"assist": {
+		"enabled": true,
+		"actions": {
+			"source": {
+				"organizeImports": "on"
+			}
+		}
+	},
+	"formatter": {
+		"enabled": true
+	},
+	"linter": {
+		"enabled": true,
+		"rules": {
+			"recommended": true,
+			"style": {
+				"useShorthandFunctionType": "off"
+			},
+			"correctness": {
+				"useJsxKeyInIterable": "off"
+			}
+		}
+	},
+	"overrides": [
+		{
+			"includes": ["test/**"],
+			"linter": {
+				"rules": {
+					"a11y": {
+						"useHtmlLang": "off"
+					}
+				}
+			}
+		}
+	]
+}
--- a/examples/personal-site/components/header.tsx
+++ b/examples/personal-site/components/header.tsx
@ -1,5 +1,9 @@
 import { stylesheet } from "typestyle";
-import { Component, createElement } from "websnacks";
+import {
+	type Component,
+	// biome-ignore lint/correctness/noUnusedImports: required to support JSX
+	createElement,
+} from "websnacks";

 const styles = stylesheet({
 	header: {
--- a/examples/personal-site/components/layout.tsx
+++ b/examples/personal-site/components/layout.tsx
@ -1,6 +1,10 @@
 import { normalize } from "csstips";
 import { stylesheet } from "typestyle";
-import { Component, createElement } from "websnacks";
+import {
+	type Component,
+	// biome-ignore lint/correctness/noUnusedImports: required to support JSX
+	createElement,
+} from "websnacks";

 import { stylesheetPath } from "../config";
 import { Header } from "./header";
@ -46,10 +50,7 @@ export const Layout: Component<LayoutProps> = ({ children, headline }) => (
 				{headline && ` | ${headline}`}
 			</title>
 			<meta name="description" content="" />
-            <meta
-                name="viewport"
-                content="width=device-width, initial-scale=1"
-            />
+			<meta name="viewport" content="width=device-width, initial-scale=1" />
 			<link rel="stylesheet" href={stylesheetPath} />
 		</head>

--- a/examples/personal-site/components/navbar.tsx
+++ b/examples/personal-site/components/navbar.tsx
@ -1,5 +1,9 @@
 import { stylesheet } from "typestyle";
-import { Component, createElement } from "websnacks";
+import {
+	type Component,
+	// biome-ignore lint/correctness/noUnusedImports: required to support JSX
+	createElement,
+} from "websnacks";

 const styles = stylesheet({
 	navbar: {
--- a/examples/personal-site/package-lock.json
+++ b/examples/personal-site/package-lock.json
--- a/examples/personal-site/package.json
+++ b/examples/personal-site/package.json
@ -1,5 +1,6 @@
 {
 	"name": "websnacks-example-personal-site",
+	"type": "module",
 	"scripts": {
 		"build": "websnacks -r ts-node/register build",
 		"dev": "websnacks -r ts-node/register dev"
--- a/examples/personal-site/pages/index.tsx
+++ b/examples/personal-site/pages/index.tsx
@ -1,22 +1,25 @@
-import { Component, createElement } from "websnacks";
+import {
+	type Component,
+	// biome-ignore lint/correctness/noUnusedImports: required to support JSX
+	createElement,
+} from "websnacks";

 import { Layout } from "../components/layout";

 export const page: Component = () => (
 	<Layout>
 		<p>
-            Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur
-            dapibus condimentum mauris et egestas. Quisque orci nulla, consequat
-            at erat laoreet, malesuada sodales nisi. Sed in lorem semper lorem
-            placerat fermentum a id arcu. Curabitur non aliquam tellus, sed
-            auctor lacus. Nunc sit amet lectus ultrices, sodales nisl sit amet,
-            luctus nisl. Nunc mollis imperdiet quam, eget sollicitudin leo
-            tincidunt vel. Duis felis dui, imperdiet aliquam bibendum sed,
-            auctor et dolor. Vivamus odio ipsum, venenatis in felis sed, aliquam
-            dictum turpis. Pellentesque pellentesque consequat neque, id
-            imperdiet diam molestie nec. Nullam ut vestibulum est. Pellentesque
-            orci urna, porta vel porta quis, semper ut enim. Donec sit amet urna
-            arcu. Nam tincidunt fermentum ligula a pharetra.{" "}
+			Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur dapibus
+			condimentum mauris et egestas. Quisque orci nulla, consequat at erat
+			laoreet, malesuada sodales nisi. Sed in lorem semper lorem placerat
+			fermentum a id arcu. Curabitur non aliquam tellus, sed auctor lacus. Nunc
+			sit amet lectus ultrices, sodales nisl sit amet, luctus nisl. Nunc mollis
+			imperdiet quam, eget sollicitudin leo tincidunt vel. Duis felis dui,
+			imperdiet aliquam bibendum sed, auctor et dolor. Vivamus odio ipsum,
+			venenatis in felis sed, aliquam dictum turpis. Pellentesque pellentesque
+			consequat neque, id imperdiet diam molestie nec. Nullam ut vestibulum est.
+			Pellentesque orci urna, porta vel porta quis, semper ut enim. Donec sit
+			amet urna arcu. Nam tincidunt fermentum ligula a pharetra.{" "}
 		</p>
 	</Layout>
 );
--- a/examples/personal-site/pages/projects.tsx
+++ b/examples/personal-site/pages/projects.tsx
@ -1,5 +1,9 @@
 import { stylesheet } from "typestyle";
-import { Component, createElement } from "websnacks";
+import {
+	type Component,
+	// biome-ignore lint/correctness/noUnusedImports: required to support JSX
+	createElement,
+} from "websnacks";

 import { Layout } from "../components/layout";

--- a/examples/personal-site/tsconfig.json
+++ b/examples/personal-site/tsconfig.json
@ -5,8 +5,8 @@
 		"moduleResolution": "node",
 		"jsx": "react",
 		"jsxFactory": "createElement",
-        "target": "ES2019",
-        "lib": ["ES2019"],
+		"target": "ES2018",
+		"lib": ["ES2018"],
 		"strict": true,
 		"noUnusedLocals": true,
 		"noUnusedParameters": true,
--- a/examples/personal-site/websnacks.ts
+++ b/examples/personal-site/websnacks.ts
@ -1,10 +1,10 @@
-import { promises as fs } from "fs";
-import * as path from "path";
-import { Config } from "websnacks";
+import { promises as fs } from "node:fs";
+import * as path from "node:path";
+import type { Config } from "websnacks";

 import { stylesheetPath } from "./config";

-const config: Config = {
+const _config: Config = {
 	// Watch additional files and folders for changes when the dev server is
 	// running.
 	watch: ["components/", "config.ts"],
@ -23,4 +23,3 @@ const config: Config = {
 		},
 	},
 };
-export = config;
--- a/index.d.ts
+++ b/index.d.ts
@ -4,13 +4,3 @@
 */

 export * from "./dist";
-
-import { HTMLElement } from "./dist";
-import { IntrinsicElements as JsxIntrinsics } from "./dist/jsx";
-
-declare global {
-    namespace JSX {
-        type Element = HTMLElement;
-        type IntrinsicElements = JsxIntrinsics;
-    }
-}
--- a/package-lock.json
+++ b/package-lock.json
--- a/package.json
+++ b/package.json
@ -1,14 +1,15 @@
 {
 	"name": "@websnacksjs/websnacks",
 	"description": "Minimal dependency server-side JSX for static sites",
-    "version": "0.1.0",
+	"version": "0.2.0",
 	"author": {
 		"name": "M. George Hansen",
 		"email": "mgeorge@technopolitica.com"
 	},
 	"license": "MPL-2.0",
+	"repository": "github:websnacksjs/websnacks",
 	"engines": {
-        "node": ">=12"
+		"node": ">=18"
 	},
 	"main": "dist/index.js",
 	"types": "types.d.ts",
@ -23,21 +24,26 @@
 	],
 	"scripts": {
 		"build": "tsc",
+		"check": "biome check .",
 		"clean": "ts-node scripts/clean.ts",
-        "prepublishOnly": "npm run clean && npm run build"
+		"prepublishOnly": "npm run reset && npm test",
+		"pretest": "npm run build",
+		"preversion": "npm run reset && npm test",
+		"release": "npm version",
+		"reset": "npm run clean && npm ci",
+		"test": "npm run test:unit && npm run test:e2e",
+		"test:unit": "cd test && ts-node --script-mode ./run-tests.ts",
+		"test:e2e": "cd test && ts-node --script-mode ./run-e2e.ts"
 	},
 	"devDependencies": {
-        "@types/node": "~12",
-        "@types/ws": "^7.2.4",
-        "@typescript-eslint/eslint-plugin": "^2.24.0",
-        "@typescript-eslint/parser": "^2.24.0",
-        "eslint": "^6.8.0",
-        "eslint-config-prettier": "^6.11.0",
-        "ts-node": "^8.10.1",
-        "typescript": "~3.8.3"
+		"@biomejs/biome": "2.4.14",
+		"@types/node": "~18",
+		"@types/ws": "^8.18.1",
+		"ts-node": "^10.9.2",
+		"typescript": "~4.9.5"
 	},
 	"optionalDependencies": {
-        "node-watch": "^0.6.3",
-        "ws": "^7.2.5"
+		"node-watch": "^0.7.4",
+		"ws": "^8.20.0"
 	}
 }
--- a/scripts/clean.ts
+++ b/scripts/clean.ts
@ -3,10 +3,29 @@
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

-import * as fs from "fs";
-import * as path from "path";
+import * as fs from "node:fs";
+import * as path from "node:path";

 const ROOT_DIR = path.resolve(__dirname, "..");
 const DIST_DIR = path.join(ROOT_DIR, "dist");
+const TEST_DIR = path.join(ROOT_DIR, ".temp");

-fs.rmdirSync(DIST_DIR, { recursive: true });
+const rmdirRecursive = (dirPath: string): void => {
+	if (!fs.existsSync(dirPath)) {
+		return;
+	}
+	const entryNames = fs.readdirSync(dirPath);
+	for (const entryName of entryNames) {
+		const entryPath = path.join(dirPath, entryName);
+		const dirent = fs.lstatSync(entryPath);
+		if (dirent.isDirectory()) {
+			rmdirRecursive(entryPath);
+		} else {
+			fs.unlinkSync(entryPath);
+		}
+	}
+	fs.rmdirSync(dirPath);
+};
+
+rmdirRecursive(DIST_DIR);
+rmdirRecursive(TEST_DIR);
--- a/src/build.ts
+++ b/src/build.ts
@ -3,12 +3,12 @@
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

-import { promises as fs } from "fs";
-import * as path from "path";
+import { promises as fs } from "node:fs";
+import * as path from "node:path";

-import { Config, ConfigPaths } from "./config";
+import type { Config, ConfigPaths } from "./config";
 import { renderPage } from "./render";
-import { purgeModuleAndDepsFromCache, walkDir } from "./utils";
+import { decacheModule, walkDir } from "./utils";

 const renderPagesToHtml = async ({
 	pagesDir,
@ -22,20 +22,19 @@ const renderPagesToHtml = async ({
 		}

 		// Ensure that we don't cache page modules when running in dev server.
-        purgeModuleAndDepsFromCache(srcPath);
+		decacheModule(srcPath);
+		// eslint-disable-next-line @typescript-eslint/no-var-requires
 		const pageSrc = require(srcPath);
 		if (!("page" in pageSrc)) {
 			throw new Error(
-                `page source at ${srcPath} does not export a "page" variable`
+				`page source at ${srcPath} does not export a "page" variable`,
 			);
 		}
-        let compiledHtml;
+		let compiledHtml: string;
 		try {
 			compiledHtml = renderPage(pageSrc.page());
 		} catch (error) {
-            throw new Error(
-                `failed to compile ${srcPath}: ${error.stack ?? error}`
-            );
+			throw new Error(`failed to compile ${srcPath}: ${error}`);
 		}
 		const relPath = path.relative(pagesDir, path.dirname(srcPath));
 		let baseName = path.basename(srcPath, ".tsx");
@ -47,7 +46,7 @@ const renderPagesToHtml = async ({
 			(async () => {
 				await fs.mkdir(path.dirname(destPath), { recursive: true });
 				await fs.writeFile(destPath, compiledHtml);
-            })()
+			})(),
 		);
 	}
 	await Promise.all(deferred);
@ -59,7 +58,7 @@ const copyStaticAssets = async ({
 }: ConfigPaths): Promise<void> => {
 	try {
 		await fs.access(staticAssetsDir);
-    } catch (error) {
+	} catch (_error) {
 		// Static assets folder doesn't exist, so no-op.
 		return;
 	}
@ -72,7 +71,7 @@ const copyStaticAssets = async ({
 			(async () => {
 				await fs.mkdir(path.dirname(destPath), { recursive: true });
 				await fs.copyFile(assetPath, destPath);
-            })()
+			})(),
 		);
 	}
 	await Promise.all(deferred);
--- a/src/cli/commands/build.ts
+++ b/src/cli/commands/build.ts
@ -5,7 +5,7 @@

 import { renderSite } from "../../build";
 import { loadConfig } from "../../config";
-import { Command, UsageError } from "../types";
+import { type Command, UsageError } from "../types";

 const helpText = `\
 Usage: websnacks build [ROOT_DIR]
--- a/src/cli/commands/dev.ts
+++ b/src/cli/commands/dev.ts
@ -3,33 +3,34 @@
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

-import { existsSync, promises as fs, watch } from "fs";
-import * as http from "http";
-import * as path from "path";
+import { existsSync, promises as fs, watch } from "node:fs";
+import * as http from "node:http";
+import * as path from "node:path";

 import { renderSite } from "../../build";
-import { Config, loadConfig } from "../../config";
-import { Command, UsageError } from "../types";
+import { type Config, loadConfig } from "../../config";
+import { isErrnoException } from "../../utils/error";
+import { type Command, UsageError } from "../types";

-const SERVER_PORT = 8080;
+const DEFAULT_SERVER_PORT = 8080;

-const injectLiveReloadScript = (htmlContents: string): string =>
+const injectLiveReloadScript = (htmlContents: string, port: number): string =>
 	htmlContents.replace(
 		"</html>",
 		`
        <script>
-            const ws = new WebSocket("ws://127.0.0.1:${SERVER_PORT}");
+            const ws = new WebSocket("ws://127.0.0.1:${port}");
            ws.onmessage = function() {
                console.log('dev server requested reload, reloading...');
                location.reload();
            };
        </script>
        </html>
-    `
+    `,
 	);

 const guessMimeType = (ext: string): string => {
-    let mimeType;
+	let mimeType: string;
 	switch (ext) {
 		case ".apng":
 			mimeType = "image/apng";
@ -118,8 +119,23 @@ const guessMimeType = (ext: string): string => {
 	return mimeType;
 };

-const serve = (publicDir: string): http.Server => {
-    const server = http.createServer(async (req, res) => {
+const portFromServer = (
+	addrInfo: { port: number } | object | string | undefined | null,
+): number => {
+	if (
+		typeof addrInfo !== "object" ||
+		addrInfo == null ||
+		!("port" in addrInfo)
+	) {
+		throw new Error(
+			"server address does not have a valid port (this should never happen!)",
+		);
+	}
+	return addrInfo.port;
+};
+
+const startHttpServer = async (publicDir: string): Promise<http.Server> => {
+	const httpServer = http.createServer(async (req, res) => {
 		if (req.url == null) {
 			res.writeHead(404);
 			res.end();
@ -133,10 +149,10 @@ const serve = (publicDir: string): http.Server => {
 			reqExt = ".html";
 		}

-        let contents;
+		let contents: Buffer | string;
 		try {
 			contents = await fs.readFile(path.join(publicDir, reqPath));
-        } catch (error) {
+		} catch (_error) {
 			console.error(`unable to load file ${reqPath}`);
 			res.writeHead(404);
 			res.end();
@ -144,31 +160,57 @@ const serve = (publicDir: string): http.Server => {
 		}
 		const mimeType = guessMimeType(reqExt);
 		if (mimeType === "text/html") {
-            contents = injectLiveReloadScript(contents.toString("utf8"));
+			const port = portFromServer(req.socket.address());
+			contents = injectLiveReloadScript(contents.toString("utf8"), port);
 		}
 		res.writeHead(200, {
 			"Content-Type": mimeType,
 		});
 		res.end(contents);
 	});
-    return server;
+	const listen = async (port?: number): Promise<void> =>
+		new Promise((resolve, reject) => {
+			httpServer
+				.once("error", (error) => reject(error))
+				.once("listening", () => resolve())
+				.listen(port);
+		});
+	try {
+		await listen(DEFAULT_SERVER_PORT);
+	} catch (error) {
+		if (
+			error instanceof Error &&
+			isErrnoException(error) &&
+			error.code !== "EADDRINUSE"
+		) {
+			throw error;
+		}
+		await listen();
+	}
+	const port = portFromServer(httpServer.address());
+	console.log(`Listening at http://127.0.0.1:${port}`);
+	return httpServer;
 };

 const startWebSocketServer = async (
-    server: http.Server
+	httpServer: http.Server,
 ): Promise<import("ws").Server | undefined> => {
 	// Attempt to load the ws module, aborting if it isn't available.
-    let ws;
+	let ws: typeof import("ws");
 	try {
 		ws = await import("ws");
 	} catch (error) {
-        if (error.code !== "MODULE_NOT_FOUND") {
+		if (
+			error instanceof Error &&
+			isErrnoException(error) &&
+			error.code !== "MODULE_NOT_FOUND"
+		) {
 			throw error;
 		}
 		console.warn(`'ws' module not found, live-reloading will be disabled`);
 		return;
 	}
-    const wsServer = new ws.Server({ server });
+	const wsServer = new ws.Server({ server: httpServer });
 	wsServer.on("connection", () => {
 		console.log("connected to dev site");
 	});
@ -177,28 +219,32 @@ const startWebSocketServer = async (

 const watchFolders = async (
 	folders: string[],
-    listener: (eventType: "update" | "remove", fileName: string) => void
+	listener: (eventType?: "update" | "remove", fileName?: string) => void,
 ): Promise<void> => {
 	// Try to load node-watch, falling back to fs watch if node-watch isn't
 	// available.
 	try {
-        const { default: watch } = await import("node-watch");
-        watch(folders, { recursive: true }, listener);
+		const nodeWatch = await import("node-watch");
+		nodeWatch.default(folders, { recursive: true }, listener);
 		return;
 	} catch (error) {
-        if (error.code !== "MODULE_NOT_FOUND") {
+		if (
+			error instanceof Error &&
+			isErrnoException(error) &&
+			error.code !== "MODULE_NOT_FOUND"
+		) {
 			throw error;
 		}
 		console.warn(
 			`'node-watch' module not found, falling back to fs.watch (may ` +
-                `result in file watch issues on some OSes)`
+				"result in file watch issues on some OSes)",
 		);
 	}
 	// NOTE: fs.watch has significant cross-platform issues, including
 	//       triggering duplicate file events on some systems.
 	for (const folder of folders) {
 		watch(folder, { recursive: true }, (_, fileName) => {
-            listener("update", fileName);
+			listener("update", fileName || undefined);
 		});
 	}
 };
@ -244,19 +290,18 @@ const devCommand: Command = {
 		};
 		const config = await rebuild();
 		const { outDir } = config.paths;
-        const httpServer = serve(outDir);
+		const httpServer = await startHttpServer(outDir);
 		const wsServer = await startWebSocketServer(httpServer);
-        httpServer.listen(SERVER_PORT, () => {
-            console.log(`Listening at http://127.0.0.1:${SERVER_PORT}`);
-        });
 		const watchedFolders = config.watch.filter((filePath) =>
-            existsSync(filePath)
+			existsSync(filePath),
 		);
-        watchFolders(watchedFolders, async (event, filePath) => {
-            console.log(`${filePath}:${event} triggering rebuild...`);
+		await watchFolders(watchedFolders, async (event, filePath) => {
+			const filePathForLog = filePath || "<UNKNOWN_FILE>";
+			const eventForLog = event || "<UNKNOWN_EVENT>";
+			console.log(`${filePathForLog}:${eventForLog} triggering rebuild...`);
 			await rebuild();
 			if (wsServer != null) {
-                console.log(`rebuild finished, reloading browsers...`);
+				console.log("rebuild finished, reloading browsers...");
 				for (const ws of wsServer.clients) {
 					ws.send("reload");
 				}
--- a/src/cli/index.ts
+++ b/src/cli/index.ts
@ -3,7 +3,7 @@
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

-import { Command, UsageError } from "./types";
+import { type Command, UsageError } from "./types";

 const globalHelpText = `\
 Usage: websnacks [...globalOptions] <command>
@ -24,7 +24,7 @@ interface Options {
 }

 const parseArgs = (
-    args: string[]
+	args: string[],
 ): { options: Options; commandName?: string; commandArgs: string[] } => {
 	const options: Options = {
 		showHelp: false,
@ -36,20 +36,22 @@ const parseArgs = (
 		const opt = args.shift();
 		switch (opt) {
 			case "-h":
-            case "--help":
+			case "--help": {
 				options.showHelp = true;
 				break;
+			}
 			case "-r":
-            case "--require":
+			case "--require": {
 				const moduleName = args.shift();
 				if (moduleName == null) {
 					throw new UsageError(
-                        `-r requires a valid module name`,
-                        globalHelpText
+						"-r requires a valid module name",
+						globalHelpText,
 					);
 				}
 				options.require.push(moduleName);
 				break;
+			}
 			default:
 				throw new UsageError(`unknown option ${opt}`, globalHelpText);
 		}
@ -65,7 +67,7 @@ const _main = async (args: string[]): Promise<void> => {
 		return;
 	}
 	if (commandName == null) {
-        throw new UsageError(`must specify a valid command`, globalHelpText);
+		throw new UsageError("must specify a valid command", globalHelpText);
 	}
 	for (const moduleName of options.require) {
 		await import(moduleName);
@ -80,10 +82,7 @@ const _main = async (args: string[]): Promise<void> => {
 			command = await import("./commands/dev");
 			break;
 		default:
-            throw new UsageError(
-                `unknown command ${commandName}`,
-                globalHelpText
-            );
+			throw new UsageError(`unknown command ${commandName}`, globalHelpText);
 	}
 	// NOTE: Should this just delegate to the command?
 	for (const arg of commandArgs) {
--- a/src/component.ts
+++ b/src/component.ts
@ -25,15 +25,28 @@ export interface HTMLElement {
 /**
 * All valid types of elements that can be rendered to HTML.
 */
-export type Element = HTMLElement | string | boolean | undefined | null;
+export type Element =
+	| Element[]
+	| HTMLElement
+	| string
+	| number
+	| boolean
+	| undefined
+	| null;

 /**
 * Custom HTMLElement factory that can be parameterized by props.
 */
-export interface Component<P extends object = {}> {
+export interface Component<P extends object = Record<string, unknown>> {
 	(
 		props: P & {
 			children?: Element[];
-        }
+		},
 	): HTMLElement;
 }
+
+export const Fragment: Component = ({ children }) => ({
+	tag: "#fragment",
+	attributes: {},
+	children: children || [],
+});
--- a/src/config.ts
+++ b/src/config.ts
@ -3,9 +3,9 @@
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

-import * as path from "path";
+import * as path from "node:path";

-import { purgeModuleAndDepsFromCache } from "./utils";
+import { decacheModule } from "./utils";

 /**
 * Paths used during configuration.
@ -47,6 +47,7 @@ export interface Config {
 	watch: string[];
 }

+// eslint-disable-next-line @typescript-eslint/no-empty-function
 const noop = () => {};

 /**
@ -57,13 +58,31 @@ const noop = () => {};
 * @return Fully-realized configuration.
 */
 export const loadConfig = async (rootDir: string): Promise<Config> => {
-    const configPath = require.resolve(path.resolve(rootDir, "websnacks"));
-    purgeModuleAndDepsFromCache(configPath);
+	let configPath = "";
+	let userConfig: UserConfig = {};
+	// Attempt to load a websnacks.ts/js file in rootDir.
+	try {
+		configPath = require.resolve(path.resolve(rootDir, "websnacks"));
+		decacheModule(configPath);
 		// TODO: validate user config.
-    const userConfig = await import(configPath);
+		userConfig = await import(configPath);
+	} catch (_error) {
+		// Use default config;
+	}
 	const outDir = path.join(rootDir, "public");
 	const pagesDir = path.join(rootDir, "pages");
 	const staticAssetsDir = path.join(rootDir, "static");
+
+	const watch = [pagesDir, staticAssetsDir];
+	if (configPath) {
+		watch.push(path.relative(rootDir, configPath));
+	}
+	if (userConfig.watch != null) {
+		for (const userWatch of userConfig.watch) {
+			watch.push(path.relative(rootDir, userWatch));
+		}
+	}
+
 	return {
 		paths: {
 			rootDir,
@ -75,11 +94,8 @@ export const loadConfig = async (rootDir: string): Promise<Config> => {
 			afterSiteRender: noop,
 			...userConfig.hooks,
 		},
-        watch: [
-            ...userConfig.watch.map((p: string) => path.relative(rootDir, p)),
-            path.relative(rootDir, configPath),
-            pagesDir,
-            staticAssetsDir,
-        ],
+		watch,
 	};
 };
+
+export const defineConfig = (userConfig: UserConfig): UserConfig => userConfig;
--- a/src/create-element.ts
+++ b/src/create-element.ts
@ -3,8 +3,9 @@
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

-import { Component, Element, HTMLElement } from "./component";
-import { HTMLAttributes } from "./jsx";
+import type { Component, Element, HTMLElement } from "./component";
+import type { HTMLAttributes } from "./jsx";
+import { flatDeep } from "./utils";

 /**
 * Create an HTMLElement from a custom Component.
@ -37,12 +38,12 @@ export function createElement(
 	...children: Element[]
 ): HTMLElement;
 export function createElement(
-    type: string | Component<any>,
-    props: (HTMLAttributes & Record<string, any>) | null,
+	type: string | Component,
+	props: object | null,
 	...children: Element[]
 ): HTMLElement {
 	// Flatten the children array so we can accept arrays as children.
-    const normalizedChildren = children.flat();
+	const normalizedChildren = flatDeep(children);
 	if (type instanceof Function) {
 		return type({ ...props, children: normalizedChildren });
 	}
@ -50,5 +51,26 @@ export function createElement(
 	if (type !== type.toLowerCase()) {
 		console.warn(`constructed HTML5 tag with non-lowercase name ${type}`);
 	}
-    return { tag: type, attributes: props || {}, children: normalizedChildren };
+	const attrs: Record<string, string | number | boolean> = {};
+	for (const [key, value] of Object.entries(props || {})) {
+		if (key === "dangerouslySetInnerHTML") {
+			if (children.length > 0) {
+				throw new Error(
+					'An element with children may not have a "dangerouslySetInnerHTML" prop since children would be overriden',
+				);
+			}
+			attrs[key] = value.__html;
+			continue;
+		}
+		if (
+			typeof value !== "string" &&
+			typeof value !== "number" &&
+			typeof value !== "boolean"
+		) {
+			console.warn(`non-primitive attribute ${key} = ${JSON.stringify(value)}`);
+			continue;
+		}
+		attrs[key] = value;
+	}
+	return { tag: type, attributes: attrs, children: normalizedChildren };
 }
--- a/src/index.ts
+++ b/src/index.ts
@ -3,6 +3,7 @@
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

-export { HTMLElement, Component } from "./component";
-export { UserConfig as Config } from "./config";
+export { Component, Fragment, HTMLElement } from "./component";
+export { defineConfig, UserConfig as Config } from "./config";
 export { createElement } from "./create-element";
+export * from "./jsx";
--- a/src/jsx.ts
+++ b/src/jsx.ts
@ -3,10 +3,13 @@
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+import type { HTMLElement } from "./component";
+
 export interface RdfaAttributes {
 	about?: string;
 	datatype?: string;
-    inlist?: any;
+	inlist?: boolean;
 	prefix?: string;
 	property?: string;
 	resource?: string;
@ -22,7 +25,14 @@ export interface MicrodataAttributes {
 	itemRef?: string;
 }

-export interface HTMLAttributes extends RdfaAttributes, MicrodataAttributes {
+export interface SetInnerHtmlAttributes {
+	dangerouslySetInnerHTML?: { __html: string };
+}
+
+export interface HTMLAttributes
+	extends RdfaAttributes,
+		MicrodataAttributes,
+		SetInnerHtmlAttributes {
 	accept?: string;
 	acceptCharset?: string;
 	accessKey?: string;
@ -60,7 +70,7 @@ export interface HTMLAttributes extends RdfaAttributes, MicrodataAttributes {
 	dir?: "auto" | "rtl" | "ltr";
 	disabled?: boolean;
 	disableRemotePlayback?: boolean;
-    download?: any;
+	download?: boolean | string;
 	draggable?: boolean;
 	encType?: string;
 	form?: string;
@ -154,7 +164,10 @@ export interface HTMLAttributes extends RdfaAttributes, MicrodataAttributes {
 	wrap?: string;
 }

-export interface IntrinsicElements {
+declare global {
+	namespace JSX {
+		type Element = HTMLElement;
+		type IntrinsicElements = {
 			a: HTMLAttributes;
 			abbr: HTMLAttributes;
 			address: HTMLAttributes;
@ -270,4 +283,6 @@ export interface IntrinsicElements {
 			var: HTMLAttributes;
 			video: HTMLAttributes;
 			wbr: HTMLAttributes;
+		};
+	}
 }
--- a/src/render.ts
+++ b/src/render.ts
@ -3,7 +3,7 @@
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

-import { Element, HTMLElement } from "./component";
+import type { Element, HTMLElement } from "./component";

 const HTML_ESCAPES: { [char: string]: string } = {
 	"&": "&amp;",
@ -22,20 +22,34 @@ const renderElement = (elem: Element): string => {
 	if (elem == null || typeof elem === "boolean") {
 		return "";
 	}
+	if (typeof elem === "number") {
+		return elem.toString();
+	}
 	if (typeof elem === "string") {
 		return escapeHtml(elem);
 	}
+	if (Array.isArray(elem)) {
+		return elem.map((e) => renderElement(e)).join("");
+	}

 	let output = "";
 	output += startTag(elem);
+	if (elem.attributes.dangerouslySetInnerHTML != null) {
+		output += elem.attributes.dangerouslySetInnerHTML;
+	} else {
 		for (const child of elem.children) {
 			output += renderElement(child);
 		}
+	}
 	output += endTag(elem);
 	return output;
 };

 const startTag = (elem: HTMLElement): string => {
+	if (elem.tag === "#fragment") {
+		return "";
+	}
+
 	let output = `<${escapeHtml(elem.tag)}`;

 	for (const [attrName, attrValue] of Object.entries(elem.attributes)) {
@ -45,6 +59,11 @@ const startTag = (elem: HTMLElement): string => {
 			continue;
 		}

+		// Ignore the special attr for setting raw inner HTML.
+		if (attrName === "dangerouslySetInnerHTML") {
+			continue;
+		}
+
 		let normalizedAttrName = escapeHtml(attrName.toLowerCase());
 		if (normalizedAttrName === "classname") {
 			normalizedAttrName = "class";
@ -52,9 +71,7 @@ const startTag = (elem: HTMLElement): string => {
 		if (attrValue === true) {
 			output += ` ${normalizedAttrName}=""`;
 		} else {
-            output += ` ${normalizedAttrName}="${escapeAttr(
-                attrValue.toString()
-            )}"`;
+			output += ` ${normalizedAttrName}="${escapeAttr(attrValue.toString())}"`;
 		}
 	}

@ -62,7 +79,12 @@ const startTag = (elem: HTMLElement): string => {
 	return output;
 };

-const endTag = (elem: HTMLElement): string => `</${escapeHtml(elem.tag)}>`;
+const endTag = (elem: HTMLElement): string => {
+	if (elem.tag === "#fragment") {
+		return "";
+	}
+	return `</${escapeHtml(elem.tag)}>`;
+};

 /**
 * Render a complete HTML page from an HTMLElement. Note that the root element
@ -72,10 +94,20 @@ const endTag = (elem: HTMLElement): string => `</${escapeHtml(elem.tag)}>`;
 *
 * @return Fully rendered HTML document as a string.
 */
-export const renderPage = (rootElem: HTMLElement): string => {
+export const renderPage = (rootElem: Element): string => {
+	if (rootElem == null) {
+		throw new Error("root page element cannot be null");
+	}
+	if (typeof rootElem !== "object" || !("tag" in rootElem)) {
+		throw new Error(
+			`root page element must be a valid HTMLElement, got ${JSON.stringify(
+				rootElem,
+			)}`,
+		);
+	}
 	if (rootElem.tag.toLowerCase() !== "html") {
 		throw new Error(
-            `attempted to render page with non-HTML root element ${rootElem.tag}`
+			`attempted to render page with non-HTML root element ${rootElem.tag}`,
 		);
 	}

--- a/src/utils.ts
+++ b/src/utils.ts
@ -1,50 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at https://mozilla.org/MPL/2.0/.
- */
-
-import { promises as fs } from "fs";
-import * as path from "path";
-
-/**
- * Recursively walk a directory, returning the files it finds.
- *
- * @param dirPath Path to the directory to walk.
- *
- * @return Generator that yields the files found while walking the directory.
- */
-export const walkDir = async function* (
-    dirPath: string
-): AsyncGenerator<string> {
-    const dirEnts = await fs.readdir(dirPath, { withFileTypes: true });
-    for (const dirEnt of dirEnts) {
-        if (dirEnt.isDirectory()) {
-            yield* walkDir(path.join(dirPath, dirEnt.name));
-        }
-        if (dirEnt.isFile()) {
-            yield path.join(dirPath, dirEnt.name);
-        }
-    }
-};
-
-/**
- * Purge cached versions of a node module and all of its dependencies from the
- * global require cache, ensuring that future imports reload the module from
- * disk.
- *
- * @param modName Name of the module to purge from the require cache.
- */
-export const purgeModuleAndDepsFromCache = (modName: string): void => {
-    var modPath = require.resolve(modName);
-    if (modPath == null) {
-        return;
-    }
-    const mod = require.cache[modPath];
-    if (mod == null) {
-        return;
-    }
-    for (const child of mod.children) {
-        purgeModuleAndDepsFromCache(child.id);
-    }
-    delete require.cache[modPath];
-};
--- a/src/utils/decache-module.ts
+++ b/src/utils/decache-module.ts
@ -0,0 +1,75 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+import { isErrnoException } from "./error";
+
+const resolveModulePath = (importPath: string): string | undefined => {
+	try {
+		return require.resolve(importPath);
+	} catch (error) {
+		if (
+			error instanceof Error &&
+			isErrnoException(error) &&
+			error.code === "MODULE_NOT_FOUND"
+		) {
+			return;
+		}
+		throw error;
+	}
+};
+
+const removeParentModuleRef = (mod: NodeModule): void => {
+	const parent = mod.parent;
+	if (parent == null) {
+		return;
+	}
+
+	const siblings = parent.children;
+	const nSiblings = siblings.length;
+	for (let i = nSiblings - 1; i >= 0; i--) {
+		const sibling = siblings[i];
+		if (sibling.id === mod.id) {
+			siblings.splice(i, 1);
+			return;
+		}
+	}
+};
+
+/**
+ * Clear a module and its dependencies from node's module cache, ensuring that
+ * requiring the module again will reload the code from disk.
+ *
+ * @param importPath Path or name of the module to resolve (same as
+ *        {@see require}).
+ *
+ * @throws Error if the module could not be resolved due to filesystem error.
+ */
+export const decacheModule = (importPath: string): void => {
+	const modulePath = resolveModulePath(importPath);
+	if (modulePath == null) {
+		return;
+	}
+
+	// DFS the module dependency tree, using iteration to avoid stack size
+	// exceeded exceptions.
+	const modsToCheck: NodeModule[] = [];
+	const visited: Set<string> = new Set();
+	let currentMod: NodeModule | undefined = require.cache[modulePath];
+	while (currentMod != null) {
+		if (visited.has(currentMod.id)) {
+			currentMod = modsToCheck.pop();
+			continue;
+		}
+
+		removeParentModuleRef(currentMod);
+		delete require.cache[currentMod.id];
+		for (const childMod of currentMod.children) {
+			modsToCheck.push(childMod);
+		}
+
+		visited.add(currentMod.id);
+		currentMod = modsToCheck.pop();
+	}
+};
--- a/src/utils/error.ts
+++ b/src/utils/error.ts
@ -0,0 +1,3 @@
+export const isErrnoException = (
+	error: Error,
+): error is NodeJS.ErrnoException => "code" in error;
--- a/src/utils/index.ts
+++ b/src/utils/index.ts
@ -0,0 +1,51 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+import { promises as fs } from "node:fs";
+import * as path from "node:path";
+
+export { decacheModule } from "./decache-module";
+
+/**
+ * Recursively walk a directory, returning the files it finds.
+ *
+ * @param dirPath Path to the directory to walk.
+ *
+ * @return Generator that yields the files found while walking the directory.
+ */
+export const walkDir = async function* (
+	dirPath: string,
+): AsyncGenerator<string> {
+	const dirEnts = await fs.readdir(dirPath, { withFileTypes: true });
+	for (const dirEnt of dirEnts) {
+		if (dirEnt.isDirectory()) {
+			yield* walkDir(path.join(dirPath, dirEnt.name));
+		}
+		if (dirEnt.isFile()) {
+			yield path.join(dirPath, dirEnt.name);
+		}
+	}
+};
+
+export type Flattenable<T> = Array<T | Flattenable<T>>;
+
+/**
+ * Flatten an arbitrarily-deeply nested array into a flat array.
+ *
+ * @param arr Array to flatten.
+ *
+ * @return Flattened array.
+ */
+export const flatDeep = <T>(arr: Flattenable<T>): T[] => {
+	const flattenedArr: T[] = [];
+	for (const val of arr) {
+		if (Array.isArray(val)) {
+			flattenedArr.push(...flatDeep(val));
+		} else {
+			flattenedArr.push(val);
+		}
+	}
+	return flattenedArr;
+};
--- a/test/e2e/build.tsx
+++ b/test/e2e/build.tsx
@ -0,0 +1,151 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+import { promises as fs } from "node:fs";
+import * as path from "node:path";
+
+import {
+	npmCmd,
+	runCommand,
+	WEBSNACKS_BIN_PATH,
+	WEBSNACKS_REPO_ROOT,
+	withTempDir,
+} from "../helpers/e2e";
+import { testSuite } from "../lib";
+
+testSuite("build command", ({ test }) => {
+	test("runs without throwing error", async () => {
+		await withTempDir(async (tempDirPath) => {
+			await fs.writeFile(
+				path.join(tempDirPath, "tsconfig.json"),
+				JSON.stringify({
+					compilerOptions: {
+						esModuleInterop: true,
+						module: "CommonJS",
+						moduleResolution: "node",
+						jsx: "react",
+						jsxFactory: "createElement",
+						target: "ES2018",
+						lib: ["ES2018"],
+						strict: true,
+						noUnusedLocals: true,
+						noUnusedParameters: true,
+						noImplicitReturns: true,
+						noFallthroughCasesInSwitch: true,
+					},
+					include: ["components/**/*", "pages/**/*"],
+				}),
+				{
+					encoding: "utf8",
+				},
+			);
+			await fs.writeFile(
+				path.join(tempDirPath, "websnacks.ts"),
+				`
+                import { Config } from "websnacks";
+                const config: Config = {
+                    watch: [],
+                };
+                export = config;
+                `,
+				{
+					encoding: "utf8",
+				},
+			);
+			const pagesPath = path.join(tempDirPath, "pages");
+			await fs.mkdir(pagesPath);
+			await fs.writeFile(
+				path.join(pagesPath, "index.tsx"),
+				`
+                import { createElement } from "websnacks";
+                export const page = () => <html />;
+                `,
+				{
+					encoding: "utf8",
+				},
+			);
+			await fs.writeFile(
+				path.join(tempDirPath, "package.json"),
+				JSON.stringify({
+					devDependencies: {
+						websnacks: `file:${WEBSNACKS_REPO_ROOT}`,
+					},
+				}),
+				{ encoding: "utf8" },
+			);
+			await runCommand(npmCmd, ["install", "--silent"], {
+				cwd: tempDirPath,
+			}).complete;
+			const cmd = runCommand(
+				"node",
+				[WEBSNACKS_BIN_PATH, "-r", "ts-node/register", "build"],
+				{
+					cwd: tempDirPath,
+				},
+			);
+			await cmd.complete;
+		});
+	});
+
+	test("works without config file", async () => {
+		await withTempDir(async (tempDirPath) => {
+			await fs.writeFile(
+				path.join(tempDirPath, "tsconfig.json"),
+				JSON.stringify({
+					compilerOptions: {
+						esModuleInterop: true,
+						module: "CommonJS",
+						moduleResolution: "node",
+						jsx: "react",
+						jsxFactory: "createElement",
+						target: "ES2018",
+						lib: ["ES2018"],
+						strict: true,
+						noUnusedLocals: true,
+						noUnusedParameters: true,
+						noImplicitReturns: true,
+						noFallthroughCasesInSwitch: true,
+					},
+					include: ["components/**/*", "pages/**/*"],
+				}),
+				{
+					encoding: "utf8",
+				},
+			);
+			const pagesPath = path.join(tempDirPath, "pages");
+			await fs.mkdir(pagesPath);
+			await fs.writeFile(
+				path.join(pagesPath, "index.tsx"),
+				`
+                import { createElement } from "websnacks";
+                export const page = () => <html />;
+                `,
+				{
+					encoding: "utf8",
+				},
+			);
+			await fs.writeFile(
+				path.join(tempDirPath, "package.json"),
+				JSON.stringify({
+					devDependencies: {
+						websnacks: `file:${WEBSNACKS_REPO_ROOT}`,
+					},
+				}),
+				{ encoding: "utf8" },
+			);
+			await runCommand(npmCmd, ["install", "--silent"], {
+				cwd: tempDirPath,
+			}).complete;
+			const cmd = runCommand(
+				"node",
+				[WEBSNACKS_BIN_PATH, "-r", "ts-node/register", "build"],
+				{
+					cwd: tempDirPath,
+				},
+			);
+			await cmd.complete;
+		});
+	});
+});
--- a/test/e2e/dev.tsx
+++ b/test/e2e/dev.tsx
@ -0,0 +1,160 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+import { promises as fs } from "node:fs";
+import * as path from "node:path";
+
+import {
+	npmCmd,
+	runCommand,
+	WEBSNACKS_BIN_PATH,
+	WEBSNACKS_REPO_ROOT,
+	wait,
+	withTempDir,
+} from "../helpers/e2e";
+import { testSuite } from "../lib";
+
+testSuite("dev command", ({ test, expect }) => {
+	test("starts without throwing error", async () => {
+		await withTempDir(async (tempDirPath) => {
+			await fs.writeFile(
+				path.join(tempDirPath, "tsconfig.json"),
+				JSON.stringify({
+					compilerOptions: {
+						esModuleInterop: true,
+						module: "CommonJS",
+						moduleResolution: "node",
+						jsx: "react",
+						jsxFactory: "createElement",
+						target: "ES2018",
+						lib: ["ES2018"],
+						strict: true,
+						noUnusedLocals: true,
+						noUnusedParameters: true,
+						noImplicitReturns: true,
+						noFallthroughCasesInSwitch: true,
+					},
+					include: ["components/**/*", "pages/**/*"],
+				}),
+				{
+					encoding: "utf8",
+				},
+			);
+			await fs.writeFile(
+				path.join(tempDirPath, "websnacks.ts"),
+				`
+                import { Config } from "websnacks";
+                const config: Config = {
+                    watch: [],
+                };
+                export = config;
+                `,
+				{
+					encoding: "utf8",
+				},
+			);
+			const pagesPath = path.join(tempDirPath, "pages");
+			await fs.mkdir(pagesPath);
+			await fs.writeFile(
+				path.join(pagesPath, "index.tsx"),
+				`
+                import { createElement } from "websnacks";
+                export const page = () => <html />;
+                `,
+				{
+					encoding: "utf8",
+				},
+			);
+			await fs.writeFile(
+				path.join(tempDirPath, "package.json"),
+				JSON.stringify({
+					devDependencies: {
+						websnacks: `file:${WEBSNACKS_REPO_ROOT}`,
+					},
+				}),
+				{ encoding: "utf8" },
+			);
+			await runCommand(npmCmd, ["install", "--silent"], {
+				cwd: tempDirPath,
+			}).complete;
+			const cmd = runCommand(
+				"node",
+				[WEBSNACKS_BIN_PATH, "-r", "ts-node/register", "dev"],
+				{
+					cwd: tempDirPath,
+				},
+			);
+			// FIXME: This test is a bit brittle due to relying on timeouts.
+			await wait(10_000);
+			cmd.process.kill();
+			const stdout = await cmd.complete;
+			expect(stdout).toStartWith("Listening at");
+		});
+	});
+
+	test("works without config file", async () => {
+		await withTempDir(async (tempDirPath) => {
+			await fs.writeFile(
+				path.join(tempDirPath, "tsconfig.json"),
+				JSON.stringify({
+					compilerOptions: {
+						esModuleInterop: true,
+						module: "CommonJS",
+						moduleResolution: "node",
+						jsx: "react",
+						jsxFactory: "createElement",
+						target: "ES2018",
+						lib: ["ES2018"],
+						strict: true,
+						noUnusedLocals: true,
+						noUnusedParameters: true,
+						noImplicitReturns: true,
+						noFallthroughCasesInSwitch: true,
+					},
+					include: ["components/**/*", "pages/**/*"],
+				}),
+				{
+					encoding: "utf8",
+				},
+			);
+			const pagesPath = path.join(tempDirPath, "pages");
+			await fs.mkdir(pagesPath);
+			await fs.writeFile(
+				path.join(pagesPath, "index.tsx"),
+				`
+                import { createElement } from "websnacks";
+                export const page = () => <html />;
+                `,
+				{
+					encoding: "utf8",
+				},
+			);
+			await fs.writeFile(
+				path.join(tempDirPath, "package.json"),
+				JSON.stringify({
+					devDependencies: {
+						websnacks: `file:${WEBSNACKS_REPO_ROOT}`,
+					},
+				}),
+				{ encoding: "utf8" },
+			);
+			await runCommand(npmCmd, ["install", "--silent"], {
+				cwd: tempDirPath,
+			}).complete;
+			const cmd = runCommand(
+				"node",
+				[WEBSNACKS_BIN_PATH, "-r", "ts-node/register", "dev"],
+				{
+					cwd: tempDirPath,
+				},
+			);
+			// FIXME: This test is a bit brittle due to relying on timeouts.
+			await wait(10_000);
+			cmd.process.kill();
+			const stdout = await cmd.complete;
+			expect(stdout).toStartWith("Listening at");
+		});
+	});
+});
--- a/test/helpers/e2e.ts
+++ b/test/helpers/e2e.ts
@ -0,0 +1,168 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+import { type ChildProcess, spawn } from "node:child_process";
+import { promises as fs } from "node:fs";
+import * as os from "node:os";
+import * as path from "node:path";
+
+/**
+ * Set a timeout and wait for at least the specified number of milliseconds,
+ * resolving the promise once the event loop meets or exceeds timeMs.
+ *
+ * @param timeMs Time in milliseconds to wait.
+ */
+export const wait = async (timeMs: number): Promise<void> => {
+	return new Promise((resolve) => {
+		setTimeout(() => resolve(), timeMs);
+	});
+};
+
+const TEMP_PATH = path.resolve(__dirname, "..", "..", ".temp");
+
+/**
+ * Perform an operation within a unique temporary directory created within a
+ * special .test-dist folder within this websnacks repository.
+ *
+ * @note Currently the temporary folder is **not** cleaned up once the operation
+ *       has finished. I've had issues with losing work due to buggy removal
+ *       code and haven't been willing to risk it again. To cleanup these
+ *       temporary folders it should be as easy as removing the whole
+ *       ".test-dist" folder from your checkout.
+ *
+ * @param op Operation to perform which receives the fully resolved temp
+ *           directory path as its only argument.
+ */
+export const withTempDir = async (
+	op: (tempDirPath: string) => Promise<void> | void,
+): Promise<void> => {
+	await fs.mkdir(TEMP_PATH, { recursive: true });
+	const tempDirPath = await fs.mkdtemp(`${TEMP_PATH}/`);
+	try {
+		await op(tempDirPath);
+	} catch (error) {
+		throw new Error(`(${tempDirPath}): ${error}`);
+	}
+};
+
+/**
+ * Fully resolved path to the root of this websnacks repository.
+ */
+export const WEBSNACKS_REPO_ROOT = path.resolve(__dirname, "..", "..");
+/**
+ * Fully resolved path to the websnacks CLI script in this repository.
+ */
+export const WEBSNACKS_BIN_PATH = path.join(
+	WEBSNACKS_REPO_ROOT,
+	"bin",
+	"websnacks.js",
+);
+
+/**
+ * A handle to an asynchronous shell command run in a subprocess.
+ */
+export interface AsyncCommand {
+	/**
+	 * Promise that resolves with the stdout of the subprocess once the
+	 * subprocess exits with a zero-code.
+	 *
+	 * The promise rejects if the subprocess exits with a non-zero code, the
+	 * subprocess writes to its stderr, or the command failed to spawn.
+	 */
+	complete: Promise<string>;
+	/**
+	 * Handle to to child process for event-based process manipulation.
+	 */
+	process: ChildProcess;
+}
+
+/**
+ * Options used to configure {@link runCommand}.
+ */
+export interface CliOptions {
+	/**
+	 * Working directory where the command should be run. Defaults to the
+	 * current working directory.
+	 */
+	cwd?: string;
+	/**
+	 * Timeout in milliseconds after which a command that hasn't exited will
+	 * reject the promise and kill the subprocess.
+	 */
+	timeoutMs?: number;
+}
+
+const DEFAULT_CLI_OPTIONS = {
+	timeoutMs: 15_000,
+};
+
+/**
+ * Execute a shell command in a subprocess.
+ *
+ * This provides a more user-friendly promise-based interface to
+ * {@link child_process.spawn}. The obj
+ *
+ * @param command Name of the shell command to run.
+ * @param args Array of arguments to pass to the command.
+ * @param options Parameters to change how the command is run and resolved.
+ *
+ * @returns Command object for handling in client code.
+ */
+export const runCommand = (
+	command: string,
+	args: string[] = [],
+	options?: CliOptions,
+): AsyncCommand => {
+	const optionsWithDefaults = { ...DEFAULT_CLI_OPTIONS, ...options };
+	const process = spawn(command, args, {
+		...optionsWithDefaults,
+		stdio: "pipe",
+	});
+	const complete = new Promise<string>((resolve, reject) => {
+		let threwError = false;
+
+		let stdout = "";
+		process.stdout.on("data", (data) => {
+			stdout += data.toString();
+		});
+		process.stderr.on("data", (data) => {
+			threwError = true;
+			process.kill();
+			reject(new Error(`command output to stderr: ${data.toString()}`));
+		});
+
+		const timer = setTimeout(() => {
+			threwError = true;
+			process.kill();
+			reject(
+				new Error(`max timeout of ${optionsWithDefaults.timeoutMs}ms reached`),
+			);
+		}, optionsWithDefaults.timeoutMs);
+		process.on("exit", (code) => {
+			if (threwError) {
+				return;
+			}
+			clearTimeout(timer);
+			if (code !== null && code !== 0) {
+				reject(new Error(`command exited with non-zero code: ${code}`));
+				return;
+			}
+			resolve(stdout);
+		});
+		process.on("error", (error) => {
+			clearTimeout(timer);
+			if (!threwError) {
+				reject(new Error(`command errored: ${error}`));
+				threwError = true;
+			}
+		});
+	});
+	return {
+		complete,
+		process,
+	};
+};
+
+export const npmCmd = os.platform() === "win32" ? "npm.cmd" : "npm";
--- a/test/lib/expect.ts
+++ b/test/lib/expect.ts
@ -0,0 +1,208 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+import { areEqual, displayValue, matches } from "./utils";
+
+class ExpectError extends Error {
+	public constructor(reason: string, expected: unknown, actual: unknown) {
+		super(
+			`${reason}\n` +
+				`\texpected: ${displayValue(expected)}\n` +
+				`\tactual  : ${displayValue(actual)}`,
+		);
+	}
+}
+
+/**
+ * A generic expectation builder which knows nothing about the type of value it
+ * is operating upon.
+ *
+ * This is the base class expectation that allows only type-agnostic assertions
+ * upon its contained value, and all other expectation classes inherit from
+ * Expect.
+ */
+export class Expect<T> {
+	protected readonly value: T;
+
+	/**
+	 * Create a new expectation around a value.
+	 *
+	 * @param value Value to place assertions upon.
+	 */
+	public constructor(value: T) {
+		this.value = value;
+	}
+
+	/**
+	 * Expect the value to equal an expected value.
+	 *
+	 * Note that strict equality checking is used for primitives and structural
+	 * equality is used for objects.
+	 *
+	 * @param expected Expected value.
+	 *
+	 * @throws ExpectError If the actual value does not equal the expected value.
+	 */
+	public toEqual(expected: T): void {
+		if (!areEqual(this.value, expected)) {
+			throw new ExpectError(
+				"value does not equal expected",
+				expected,
+				this.value,
+			);
+		}
+	}
+}
+
+/**
+ * String-specific Expect assertions.
+ */
+export class StringExpect extends Expect<string> {
+	/**
+	 * Expect the string value to match a RegExp pattern.
+	 *
+	 * @param pattern Regular expression to match against.
+	 *
+	 * @throws ExpectError If the actual value does not match the expected
+	 *         RegExp pattern.
+	 */
+	public toMatch(pattern: RegExp): void {
+		if (!this.value.match(pattern)) {
+			throw new ExpectError(
+				"value does not match expected pattern",
+				pattern,
+				this.value,
+			);
+		}
+	}
+
+	/**
+	 * Expect the string value to start with a particular prefix.
+	 *
+	 * @param prefix Prefix that the string is expected to start with.
+	 *
+	 * @throws ExpectError If the actual value does not start with the expected
+	 *         prefix.
+	 */
+	public toStartWith(prefix: string): void {
+		if (!this.value.startsWith(prefix)) {
+			throw new ExpectError(
+				"value does not start with expected prefix",
+				prefix,
+				this.value,
+			);
+		}
+	}
+
+	/**
+	 * Expect the string value to end with a particular suffix.
+	 *
+	 * @param suffix Suffix that the string is expected to end with.
+	 *
+	 * @throws ExpectError If the actual value does not end with the expected
+	 *         suffix.
+	 */
+	public toEndWith(suffix: string): void {
+		if (!this.value.endsWith(suffix)) {
+			throw new ExpectError(
+				"value does not end with expected suffix",
+				suffix,
+				this.value,
+			);
+		}
+	}
+}
+
+/**
+ * Function-specific Expect assertions.
+ */
+export class FunctionExpect<T> extends Expect<() => T> {
+	/**
+	 * Expect the function to throw an Error with error message matching a
+	 * string or pattern.
+	 *
+	 * @param pattern String that exactly matches the error message or RegExp
+	 *        that should match the error message.
+	 *
+	 * @throws ExpectError If the function does not throw an error, throws a
+	 *         non-Error value, or throws an Error whose message does not match
+	 *         the expected pattern.
+	 */
+	public toThrowErrorMatching(pattern: string | RegExp): void {
+		try {
+			this.value();
+		} catch (error) {
+			if (!(error instanceof Error)) {
+				throw new ExpectError("function threw non-Error value", pattern, error);
+			}
+			if (!matches(error.message, pattern)) {
+				throw new ExpectError(
+					`thrown Error's message does not match pattern`,
+					pattern,
+					error.message,
+				);
+			}
+			return;
+		}
+		throw new ExpectError(
+			"function did not throw expected error",
+			pattern,
+			null,
+		);
+	}
+}
+
+/**
+ * Create an Expect assertion builder on a string value.
+ *
+ * @param str String value to place expectations upon.
+ */
+export function expect(str: string): StringExpect;
+/**
+ * Create an Expect assertion builder on a function value.
+ *
+ * Useful primarily for asserting that a function throws an expected Error,
+ * e.g.:
+ *
+ * ```ts
+ * // Passes assertion.
+ * expect(() => throw new Error('oh noes!')).toThrowErrorMatching('oh noes!');
+ *
+ * // Fails assertion since non-error value was thrown in func.
+ * expect(() => throw "oh noes!").toThrow('oh noes!');
+ *
+ * // Fails assertion since func doesn't throw.
+ * expect(() => 1 / 2).toThrowErrorMatching('oh noes!');
+ * ```
+ *
+ * @param fn Function to place expectations upon.
+ */
+export function expect<T>(fn: () => T): FunctionExpect<T>;
+/**
+ * Create an Expect assertion upon some value.
+ *
+ * Expectations are declarative assertions on values that immediately throw an
+ * Error when the assertion is violated. This abstraction allows for readable
+ * test assertions like the following:
+ *
+ * ```ts
+ * // Doesn't throw since strings are equal.
+ * expect("hai").toEqual("hai");
+ *
+ * // Throws an Error since 3 !== 2.
+ * expect(3).toEqual(2);
+ * ```
+ *
+ * @param value Value to place expectations upon.
+ */
+export function expect(value: unknown): Expect<unknown> {
+	if (typeof value === "string") {
+		return new StringExpect(value);
+	}
+	if (typeof value === "function") {
+		return new FunctionExpect(value as () => unknown);
+	}
+	return new Expect(value);
+}
--- a/test/lib/harness.ts
+++ b/test/lib/harness.ts
@ -0,0 +1,118 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+import { expect } from "./expect";
+import { displayValue, shuffle } from "./utils";
+
+interface Test {
+	readonly name: string;
+
+	runTest(): void | Promise<void>;
+}
+
+type TestResult = {
+	testName: string;
+} & (
+	| {
+			result: "pass";
+	  }
+	| {
+			result: "fail";
+			error: Error;
+	  }
+);
+
+const runTest = async (test: Test): Promise<TestResult> => {
+	let result: TestResult;
+	try {
+		await test.runTest();
+		result = {
+			testName: test.name,
+			result: "pass",
+		};
+	} catch (error) {
+		result = {
+			testName: test.name,
+			result: "fail",
+			error:
+				error instanceof Error
+					? error
+					: new Error(`threw non-error object: ${displayValue(error)}`),
+		};
+	}
+	return result;
+};
+
+/**
+ * Context object that is passed into a test suite definition.
+ */
+export interface TestSuiteContext {
+	/**
+	 * Define a test in this test suite.
+	 *
+	 * Tests are functions that pass if they are executed and don't throw (or
+	 * that resolve for async tests), and that fail if they throw an error (or
+	 * reject for async tests).
+	 *
+	 * Note that tests are executed in a random order within a test suite in
+	 * order to prevent accidentally creating order dependencies between tests,
+	 * which can result in brittle tests and is a code smell that might indicate
+	 * that the code under test is also brittle.
+	 */
+	test: (name: string, def: () => void | Promise<void>) => void;
+	/**
+	 * Expectation builder function used to build human-readable assertions and
+	 * errors.
+	 */
+	expect: typeof expect;
+}
+
+/**
+ * Define a suite of tests to run as a single unit.
+ *
+ * A test suite executes immediately, running tests in a randomly determined
+ * order.
+ *
+ * Note that currently there is no support for having multiple test suites per
+ * test file; you CAN have multiple test suites in a file but if the first test
+ * suite fails any subsequent test suites won't be executed.
+ *
+ * @param suiteName Name of the test suite for reporting.
+ * @param def Function used to declare the tests
+ */
+export const testSuite = (
+	suiteName: string,
+	def: (ctx: TestSuiteContext) => void,
+): void => {
+	const tests: Test[] = [];
+	const test = (name: string, runTest: () => void | Promise<void>): void => {
+		tests.push({ name, runTest });
+	};
+	def({ test, expect });
+
+	// Randomly shuffle the tests so that we can catch accidental order
+	// dependencies.
+	shuffle(tests);
+	(async () => {
+		const results = await Promise.all(tests.map((test) => runTest(test)));
+		let passed = 0;
+		for (const testResult of results) {
+			if (testResult.result === "fail") {
+				console.error(
+					`[TEST FAILURE] "${suiteName}": "${testResult.testName}": ` +
+						`${testResult.error.stack}\n`,
+				);
+				continue;
+			}
+			passed += 1;
+		}
+		console.info(
+			`[TEST] suite "${suiteName}": ${passed} of ${tests.length} succeeded\n\n`,
+		);
+		if (passed < tests.length) {
+			process.exitCode = 1;
+		}
+	})();
+};
--- a/test/lib/index.ts
+++ b/test/lib/index.ts
@ -0,0 +1,6 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+export { testSuite } from "./harness";
--- a/test/lib/utils.ts
+++ b/test/lib/utils.ts
@ -0,0 +1,112 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+/**
+ * Randomly rearrange the items of an array in-place.
+ *
+ * @param arr Array to shuffle.
+ */
+export const shuffle = <T>(arr: T[]): void => {
+	let j: number;
+	let x: T;
+	for (let i = arr.length - 1; i > 0; i--) {
+		j = Math.floor(Math.random() * (i + 1));
+		x = arr[i];
+		arr[i] = arr[j];
+		arr[j] = x;
+	}
+};
+
+const areArraysEqual = <T>(a: T[], b: T[]): boolean => {
+	if (a.length !== b.length) {
+		return false;
+	}
+	for (let i = 0; i < a.length; i++) {
+		if (!areEqual(a[i], b[i])) {
+			return false;
+		}
+	}
+	return true;
+};
+
+const areObjectsEqual = <T extends Record<string, unknown>>(
+	a: T,
+	b: T,
+): boolean => {
+	const aKeys = Object.keys(a) as Array<keyof T>;
+	const bKeys = Object.keys(b) as Array<keyof T>;
+	if (aKeys.length !== bKeys.length) {
+		return false;
+	}
+	for (const key of aKeys) {
+		if (!areEqual(a[key], b[key])) {
+			return false;
+		}
+	}
+	return true;
+};
+
+/**
+ * Return whether two values are structurally equal, with support for
+ * primitive values, arrays, deeply nested objects, and RegExp.
+ *
+ * @param a First value to test equality with.
+ * @param b Second value to test equality with.
+ *
+ * @return Whether the two values are structurally equal.
+ */
+export const areEqual = <T>(a: T, b: T): boolean => {
+	if (Array.isArray(a) && Array.isArray(b)) {
+		return areArraysEqual(a, b);
+	}
+	if (a instanceof RegExp && b instanceof RegExp) {
+		return a.source === b.source;
+	}
+	if (typeof a === "object" && typeof b === "object") {
+		return areObjectsEqual(
+			a as Record<string, unknown>,
+			b as Record<string, unknown>,
+		);
+	}
+	return a === b;
+};
+
+/**
+ * Return whether a string exactly matches an expected string OR matches a
+ * RegExp pattern.
+ *
+ * If the passed pattern is a string this uses strict equality checking, and
+ * if the passed pattern is a RegExp object it tests the value against it.
+ *
+ * @param value String value to test.
+ * @param pattern String or RegExp pattern to match value against.
+ */
+export const matches = (value: string, pattern: string | RegExp): boolean => {
+	if (typeof pattern === "string") {
+		return value === pattern;
+	}
+	return pattern.test(value);
+};
+
+/**
+ * Render a JavaScript value for debugging and error messages.
+ *
+ * This is essentially JSON.stringify, but with special cases for undefined (
+ * which normally isn't rendered with JSON.stringify) and RegExp (to display
+ * source for the regexp).
+ *
+ * @param value Value to render.
+ *
+ * @return Rendered value to display.
+ */
+export const displayValue = (value: unknown): string => {
+	if (value === undefined) {
+		return "undefined";
+	}
+	if (value instanceof RegExp) {
+		return value.toString();
+	}
+	return JSON.stringify(value);
+};
--- a/test/run-e2e.ts
+++ b/test/run-e2e.ts
@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+import { fork } from "node:child_process";
+import * as fs from "node:fs";
+import * as path from "node:path";
+
+import { shuffle } from "./lib/utils";
+
+const TEST_SUITES_DIR = path.join(__dirname, "e2e");
+const files = fs.readdirSync(TEST_SUITES_DIR);
+// Shuffle test suites to detect ordering dependencies between them.
+shuffle(files);
+for (const file of files) {
+	const fullPath = path.join(TEST_SUITES_DIR, file);
+	fork(path.relative(process.cwd(), fullPath)).on("exit", (code) => {
+		if (code !== 0) {
+			process.exitCode = 1;
+		}
+	});
+}
--- a/test/run-tests.ts
+++ b/test/run-tests.ts
@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+import { fork } from "node:child_process";
+import * as fs from "node:fs";
+import * as path from "node:path";
+
+import { shuffle } from "./lib/utils";
+
+const TEST_SUITES_DIR = path.join(__dirname, "test-suites");
+const files = fs.readdirSync(TEST_SUITES_DIR);
+// Shuffle test suites to detect ordering dependencies between them.
+shuffle(files);
+for (const file of files) {
+	const fullPath = path.join(TEST_SUITES_DIR, file);
+	fork(path.relative(process.cwd(), fullPath)).on("exit", (code) => {
+		if (code !== 0) {
+			process.exitCode = 1;
+		}
+	});
+}
--- a/test/test-suites/rendering.tsx
+++ b/test/test-suites/rendering.tsx
@ -0,0 +1,149 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+import { type Component, createElement, Fragment } from "../../dist";
+import { renderPage } from "../../dist/render";
+import { testSuite } from "../lib";
+
+testSuite("renderPage", ({ test, expect }) => {
+	test("throws an Error when root elem is not html tag", () => {
+		expect(() => renderPage(<div />)).toThrowErrorMatching(
+			"attempted to render page with non-HTML root element div",
+		);
+	});
+
+	test("outputs a HTML5 DOCTYPE declaration", () => {
+		const html = renderPage(<html />);
+		expect(html).toStartWith("<!DOCTYPE html>");
+	});
+
+	test("escapes HTML in tag names", () => {
+		const html = renderPage(<html>{createElement("div></div", null)}</html>);
+		expect(html).toEqual(
+			"<!DOCTYPE html><html><div&gt;&lt;/div></div&gt;&lt;/div></html>",
+		);
+	});
+
+	test("renders html attributes", () => {
+		const html = renderPage(
+			<html>
+				<div className="test" id="1" />
+			</html>,
+		);
+		expect(html).toEqual(
+			'<!DOCTYPE html><html><div class="test" id="1"></div></html>',
+		);
+	});
+
+	test("renders common html tags", () => {
+		const html = renderPage(
+			<html>
+				<head>
+					<title />
+				</head>
+				<body>
+					<div />
+				</body>
+			</html>,
+		);
+		expect(html).toEqual(
+			"<!DOCTYPE html><html><head><title></title></head><body><div></div></body></html>",
+		);
+	});
+
+	test("renders text nodes", () => {
+		const html = renderPage(<html>There are three lights!</html>);
+		expect(html).toEqual("<!DOCTYPE html><html>There are three lights!</html>");
+	});
+
+	test("renders spliced number nodes", () => {
+		const nLights = 3;
+		const html = renderPage(<html>There are {nLights} lights!</html>);
+		expect(html).toEqual("<!DOCTYPE html><html>There are 3 lights!</html>");
+	});
+
+	test("renders spliced arrays", () => {
+		const Light: Component<{ lightN: number }> = ({ lightN }) => (
+			<div>{lightN}</div>
+		);
+		const lights = [1, 2, 3];
+		const html = renderPage(
+			<html>
+				There are{" "}
+				{lights.map((lightN) => (
+					<Light lightN={lightN} />
+				))}{" "}
+				lights!
+			</html>,
+		);
+		expect(html).toEqual(
+			"<!DOCTYPE html><html>There are <div>1</div><div>2</div><div>3</div> lights!</html>",
+		);
+	});
+
+	test("renders components w/ custom properties", () => {
+		interface LightProps {
+			nLights: number;
+		}
+		const Light: Component<LightProps> = ({ nLights }) => (
+			<div>{nLights} lights</div>
+		);
+		const html = renderPage(
+			<html>
+				There are <Light nLights={3} />!
+			</html>,
+		);
+		expect(html).toEqual(
+			"<!DOCTYPE html><html>There are <div>3 lights</div>!</html>",
+		);
+	});
+
+	test("renders fragment children only", () => {
+		const html = renderPage(
+			<html>
+				<Fragment>
+					<div>test of</div>
+					<div>fragments</div>
+				</Fragment>
+			</html>,
+		);
+		expect(html).toEqual(
+			"<!DOCTYPE html><html><div>test of</div><div>fragments</div></html>",
+		);
+	});
+
+	test("renders unescaped HTML via dangerouslySetInnerHTML", () => {
+		const html = renderPage(
+			<html>
+				<div
+					dangerouslySetInnerHTML={{
+						__html: "<div>red alert!</div>",
+					}}
+				/>
+			</html>,
+		);
+		expect(html).toEqual(
+			"<!DOCTYPE html><html><div><div>red alert!</div></div></html>",
+		);
+	});
+
+	test("throws error when both dangerouslySetInnerHTML and children prop present", () => {
+		expect(() =>
+			renderPage(
+				<html>
+					<div
+						dangerouslySetInnerHTML={{
+							__html: "<div>set phasers to kill</div>",
+						}}
+					>
+						<div>set phasers to stun</div>
+					</div>
+				</html>,
+			),
+		).toThrowErrorMatching(
+			'An element with children may not have a "dangerouslySetInnerHTML" prop since children would be overriden',
+		);
+	});
+});
--- a/test/tsconfig.json
+++ b/test/tsconfig.json
@ -0,0 +1,7 @@
+{
+	"extends": "../tsconfig-base.json",
+	"compilerOptions": {
+		"jsx": "react",
+		"jsxFactory": "createElement"
+	}
+}
--- a/tsconfig-base.json
+++ b/tsconfig-base.json
@ -0,0 +1,13 @@
+{
+	"compilerOptions": {
+		"module": "CommonJS",
+		"moduleResolution": "node",
+		"target": "ES2018",
+		"lib": ["ES2018"],
+		"strict": true,
+		"noUnusedLocals": true,
+		"noUnusedParameters": true,
+		"noImplicitReturns": true,
+		"noFallthroughCasesInSwitch": true
+	}
+}
--- a/tsconfig.json
+++ b/tsconfig.json
@ -1,18 +1,9 @@
 {
+	"extends": "./tsconfig-base.json",
 	"compilerOptions": {
-        "sourceMap": true,
 		"declaration": true,
-        "esModuleInterop": true,
-        "module": "CommonJS",
-        "moduleResolution": "node",
-        "target": "ES2019",
-        "lib": ["ES2019"],
-        "outDir": "./dist",
-        "strict": true,
-        "noUnusedLocals": true,
-        "noUnusedParameters": true,
-        "noImplicitReturns": true,
-        "noFallthroughCasesInSwitch": true
+		"sourceMap": true,
+		"outDir": "./dist"
 	},
 	"include": ["src/**/*.ts"]
 }