The child_process.spawnSync() method is generally identical to spawn with the exception that the function will not return until the child process has fully closed. When a timeout has been encountered and killSignal is sent, the method won't return until the process has completely exited. If the process intercepts and handles the SIGTERM signal and doesn't exit, the parent process will wait until the child process has exited.
If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.