chore: implement server onExit utility

src/server/util.tsx

@@ -0,0 +1,38 @@
+export const onExit = (cb: () => void) => {
+  /*
+  const origCb = cb;
+  cb = () => {
+    origCb();
+    console.log("finished");
+  };
+  */
+  const cbAndExit = () => {
+    cb();
+    process.exit();
+  };
+
+  const exitSignals = [
+    "SIGINT",
+    "SIGTERM",
+    "uncaughtException",
+    "SIGUSR1",
+    "SIGUSR2",
+  ];
+  const cbSignals = ["beforeExit"];
+
+  for (const signal of exitSignals) {
+    process.on(signal, cbAndExit);
+  }
+  for (const signal of cbSignals) {
+    process.on(signal, cb);
+  }
+
+  return () => {
+    for (const signal of exitSignals) {
+      process.off(signal, cbAndExit);
+    }
+    for (const signal of cbSignals) {
+      process.off(signal, cb);
+    }
+  };
+};