First Beaglebone code using Bonescript. Makes the on-board LEDs cycle.

cycleblink.js

var b = require('bonescript');

// Initialize variables
var startLED = 0,
    delay = 100,
    status = b.LOW;

// Set all the onboard LEDs for OUTPUT
b.pinMode("USR0", b.OUTPUT);
b.pinMode("USR1", b.OUTPUT);
b.pinMode("USR2", b.OUTPUT);
b.pinMode("USR3", b.OUTPUT);

// Set all LEDs to low
b.digitalWrite('USR0', b.LOW);
b.digitalWrite('USR1', b.LOW);
b.digitalWrite('USR2', b.LOW);
b.digitalWrite('USR3', b.LOW);

// interval call for loop
setInterval(jump, delay);

// loop function
function jump() {
    
    //set LED pin string
    pin = "USR" + startLED;
    
    // turn LED on if off
    if (status == b.LOW) {
        pin = "USR" + startLED;
        status = b.HIGH;
        b.digitalWrite(pin, status);
    }
    
    // turn LED off if on and move to the next LED pin
    else {
        status = b.LOW;
        b.digitalWrite(pin, status);
        startLED++;
        if (startLED == 4) startLED =0;
    }
}

Can remove extra
pin = "USR" + startLED;