nodejs run a bash script using spawn

Question

I know this question has been asked many times but I have tried most of the methods and they just don't work for me. So here is my problem, I have a simple bash script like this

#!/bin/bash
echo "Username: $1";
echo  %DATABASE_URL%;

I want to run this script in a separate process. so if the parent process gets killed during my script being excused it still continues running. Here is my nodejs code

      const child = spawn('bash', [`script.sh`, 'test'], {
        detached: true,
        cwd: process.cwd(),
        detached: true,
        stdio: "inherit",
        DATABASE_URL: 'test'
      }, function (err, stdout, stderr) {
        // Node.js does not invoke this 
        console.log(stdout);
        stdout.on("data", data => {
          console.log('Output of script execution');
        });

        stderr.on("data", data => {
          console.log('an error with file system');
        });
      });
      child.unref();
      child.on('exit', (code) => {
        console.log("Child exited");
      });

So I know that my script returns some output and should run callback but it does not run it. It directly jumps to the on.('exit') callback which confuses me.

Also it worth mentioning that I am testing the code on windows and bash script.sh 'test' works if I run it on cmd.

Posts I have tried:

How to run shell script file using nodejs?

Execute script from Node in a separate process

Bash Script : what does #!/bin/bash mean?

and many of the existing weblogs that explains the same.