perf: load document libraries only when needed

public/script/lazy-assets.js

@@ -0,0 +1,24 @@
+const pending = new Map();
+// Generated from the completed library bundles, so deployments invalidate caches.
+const assets = __LAZY_ASSETS__;
+export function loadLibrary(name) {
+  if (!pending.has(name)) {
+    const script = document.createElement("script");
+    script.src = assets[name];
+    const promise = new Promise((resolve, reject) => {
+      script.onload = resolve;
+      script.onerror = () => {
+        pending.delete(name);
+        script.remove();
+        reject(new Error(`Unable to load ${name}. Please retry.`));
+      };
+    });
+    pending.set(name, promise);
+    document.head.appendChild(script);
+  }
+  return pending.get(name);
+}
+export async function loadEditor() {
+  await loadLibrary("editor");
+  ace.config.set("basePath", "/script/external/ace/");
+}