light switch with relay and raspberry pi

main.js

var gpio = require('rpi-gpio-mod');


function onoff(v) {
        gpio.setup(8, gpio.DIR_OUT, write);

        function write() {
            gpio.write(8, v, function(err) {
                if (err) throw err;
                console.log('Written to pin');
                process.exit(0)
            });
        }
}

onoff(process.argv[2]=='on')

// using rpi-gpio-mod instead of rpi-gpio is due to permission issue