var graceful = require("graceful-terminate");

graceful.add(() => console.log("Cleaning up."));

graceful.add(() => {
    ... // check some conditions
    if (notReady()){
        console.log("Cannot terminate yet");
        return true; // don't shutdown.
    }
    return false; // shutdown
});

graceful.add(() => console.log("Cleaning up."));
graceful.add(() => {
    console.log("Shutdown stops here.");
    return true;
}
graceful.add(() => console.log("Won't get here"));