Silly implementation of compass UI in console to understand how to implement it.

compass.js

function difference(a, b) {    
    var diff = b - a;
    var absDiff = Math.abs(diff);
    if (absDiff <= 180)
    {
        return absDiff == 180 ? absDiff : diff;
    }
    else if (b > a)
    {
        return absDiff - 360;
    }
    else
    {
        return 360 - absDiff;
    }
}

function pad(n, width, z) {
  z = z || '0';
  n = n + '';
  return n.length >= width ? n : new Array(width - n.length + 1).join(z) + n;
}

function draw(userDeg)
{
    // Items at different headings
    var items = [
        {label: '↑', deg: 0},
        {label: '↗', deg: 45},
        {label: '→', deg: 90},
        {label: '↘', deg: 135},
        {label: '↓', deg: 180},
        {label: '↙', deg: 225},
        {label: '←', deg: 270},
        {label: '↖', deg: 315},
    ];

    // Items to show at a given heading
    var itemsToShow = {};


    // Find items to show
    for(var i = 0; i < items.length; ++i)
    {
        var itemDeg = items[i].deg;

        var diff = difference(userDeg, itemDeg);

        // Check if item is less than 90 degrees from center (deg) and should be included    
        if (Math.abs(diff) <= 90)
        {
            items[i].diff = diff;
            itemsToShow[''+diff] = items[i].label;
        }        
    }

    process.stdout.write(pad(userDeg, 3) + '° ');
    for (var i = -90; i <= 90; ++i)
    {        
        if (i == 0)
        {
            process.stdout.write('☺');
        }
        else if (itemsToShow[i])
        {
            process.stdout.write(itemsToShow[i]);    
        }
        else 
        {
            process.stdout.write('.');
        }
    }
}

while(true)
{
    for (var i = 0; i <= 359; ++i)
    {
        process.stdout.clearLine();  // clear current text
        process.stdout.cursorTo(0);
        draw(i);
        var waitTill = new Date(new Date().getTime() + 75);
        while(waitTill > new Date()){}
    }
}