it exits with code 0 even if argument type is wrong

Should not the process ends up with non zero exit code in case of wrong argument?
For example, in this case:
```bash
node npm-delay FIVE && node sever.js
```
server should not be started, right?

At CI/CD scenario the argument can be an ENV, not hardcoded one:
```bash
node npm-delay $SERVER_START_DELAY && node sever.js
```