Works, easy :D

mod.ts

@@ -0,0 +1,23 @@
+function startProcess(args: string[] = []): Deno.Process {
+  return Deno.run({ cmd: ['deno', ...args] });
+}
+
+const throttle = 500;
+let app: Deno.Process = startProcess(Deno.args);
+let appInitTime: number = Date.now();
+let timeout: number|null = null;
+
+function runApp() {
+	appInitTime = Date.now();
+  app && app.close();
+  app = startProcess(Deno.args);
+}
+
+runApp();
+
+for await (const event of Deno.fsEvents('.')) {
+  if (event.kind !== "access") {
+    if (timeout) clearTimeout(timeout);
+    timeout = setTimeout(runApp, throttle);
+  }
+}