til/javascript/short-circuit-concurrently-when-process-fails.md

Short Circuit Concurrently When Process Fails

In Run Multiple Node Scripts Concurrently, I showed how we can get all the essential processes of our web app running concurrently in development using the concurrently package.

But what happens when there is an error and one of them exits early instead of continuing to run?

Well, the rest of the processes under the concurrently umbrella continue to run as if nothing has happened. In fact, if there is enough output, you might even miss that that one process failed since the error gets quickly pushed off the screen.

If we need every process running for our app to work, then it would be better to have the whole set of concurrent processes short circuit and exit early if one fails. We can do that by giving concurrently the --kill-others-on-fail flag.

{
  "scripts": {
    "dev": "concurrently --kill-others-on-fail \"npm:dev:*\"",
    "dev:next": "next dev",
    "dev:inngest": "pnpx inngest-cli@latest dev",
    "dev:mailhog": "mailhog",
  }
}

See the Usage section of the docs for more details.