General source code refactoring

scripts/preview.mjs

@@ -0,0 +1,38 @@
+import http from "node:http";
+import { readFile } from "node:fs/promises";
+import composition from "./compose.cjs";
+
+// Development-only routes. Never expose the workspace or forward API requests.
+const routes = new Map([
+  ["/", ["../tests/fixtures/extension.html", "text/html"]],
+  ["/extension.js", ["../tests/fixtures/extension.js", "text/javascript"]],
+  ["/consumption-trend.html", ["../tests/fixtures/consumption-trend.html", "text/html"]]
+]);
+const server = http.createServer(async (request, response) => {
+  const pathname = new URL(request.url, "http://127.0.0.1").pathname;
+  response.setHeader("Cache-Control", "no-store");
+  response.setHeader("X-Content-Type-Options", "nosniff");
+  if (request.method !== "GET") {
+    response.writeHead(405).end();
+    return;
+  }
+  try {
+    if (pathname === "/fixture-runtime.js") {
+      response.setHeader("Content-Type", "text/javascript");
+      response.end(`window.createFixtureApplication = ${composition.composeScript("content", { bootstrap: false })}`);
+      return;
+    }
+    const route = routes.get(pathname);
+    if (!route) {
+      response.writeHead(404).end();
+      return;
+    }
+    response.setHeader("Content-Type", `${route[1]}; charset=utf-8`);
+    response.end(await readFile(new URL(route[0], import.meta.url)));
+  } catch {
+    response.writeHead(500).end("Fixture could not be loaded.");
+  }
+});
+server.listen(Number(process.env.PORT) || 0, "127.0.0.1", () => {
+  console.log(`Synthetic extension preview: http://127.0.0.1:${server.address().port}/`);
+});