I want my Javascript Debug launch configuration to make sure my in-place npm server is running

I have a Javascript Debug launch configuration which starts a browser with a known URL

I have an npm launch configuration which launches an in-place dev server to handle the known URL.

I wish I could add the npm launch configuration as a "Before launch" to the Javascript Debug launch with an option to launch npm only if it has not been launched, AND to not block execution of the Javascript Debug launch even when it does launch npm.

I know I can achieve a similar effect using an External Tool launch configuration with a bash script that does this.