Simplify

static/index.js

@@ -64,6 +64,10 @@ function debounce(fn, delay) {
   };
 }
 
+// Whether the worker is currently working or not, used to avoid sending
+// multiple messages to the worker at once.
+// This will be true when the worker is compiling and executing the code, but
+// this first time it is as the worker is initialising.
 let workerWorking = true;
 let queuedWork = undefined;
 const worker = new Worker("/worker.js", { type: "module" });
@@ -80,10 +84,10 @@ function sendToWorker(code) {
 worker.onmessage = (event) => {
   // Handle the result of the compilation and execution
   const result = event.data;
-  if (!result.initialReadyMessage) clearOutput();
+  clearOutput();
   if (result.log) appendOutput(result.log, "log");
   if (result.error) appendOutput(result.error, "error");
-  for (const warning of result.warnings ?? []) {
+  for (const warning of result.warnings || []) {
     appendOutput(warning, "warning");
   }
 
@@ -94,9 +98,3 @@ worker.onmessage = (event) => {
 };
 
 editor.onUpdate(debounce((code) => sendToWorker(code), 200));
-
-// This line doesn't seem to be needed,
-// because updating the editor to the initial code (line 57)
-// triggers the onUpdate callback above (line 96) on my machine.
-// But you might uncomment it anyway to be extra safe:
-// sendToWorker(initialCode);

static/worker.js

@@ -66,4 +66,6 @@ self.onmessage = async (event) => {
   postMessage(await result);
 };
 
-postMessage({initialReadyMessage: true});
+// Send an initial message to the main thread to indicate that the worker is
+// ready to receive messages.
+postMessage({});