This is when I tried to run the code in this library on EC2:

> command
'if [ -f /sys/hypervisor/uuid ]; then echo `head -c 3 /sys/hypervisor/uuid`; fi'
> exec(command, { stdio: ["inherit", "inherit", "ignore"] })
ec2
null

Note that ec2 is not the return value of the exec. It's just printing into the same stdout.
Exec returns null!
nulll doesn't equal ec2 so it will never detect ec2 correctly