int ledPin = D2;

void setup() {
    
    pinMode( ledPin, OUTPUT );
    digitalWrite( ledPin, LOW );
    //LED is initially turned off.
    
    Particle.function( "led", ledControl );
    //register function
    
}

int ledControl( String command ) {
    
    int state = LOW;
    int val =  command.toInt( );
    //toInt mentioned in arduino's website
    //https://www.arduino.cc/reference/en/language/variables/data-types/string/functions/toint/
   
    for( int i=0; i < val; i++ ){
        
        digitalWrite( ledPin, HIGH );
        delay( 500 );
        digitalWrite(ledPin, LOW );
        delay( 500 );
    }    
    digitalWrite( ledPin, state );
    return 1;
}



void loop() {
    
}