array_lookup.js

var tvshows = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];
var show_range = 5;
var focus_pos = 0;

var ArrayLookup = function (pos) {
    // pos is beginning of Lookup Array

    var ret = [];
    // tvshows => [0, 1, 2, 3, 4]
    //
    if ((pos + show_range) > tvshows.length) {

        for (var i = pos; i < tvshows.length; i++) {
            ret.push(tvshows[i]);
        }

        for (var i = 0; i < (pos + show_range - tvshows.length); i++) {
            ret.push(tvshows[i]);
        }

    } else {
        for (var i = pos; i < (pos + show_range); i++) {
            ret.push(tvshows[i]);
        }
    }
    return ret;
}


function next() {
    focus_pos++;
    if (focus_pos > 4) {
        array_pos = array_pos + 5;
        // refresh display
        // check array_pos
        if (array_pos > tvshows.length) {
            array_pos = array_pos - tvshows.length;
        }
        display_array = ArrayLookup(array_pos);
        focus_pos = 0;
    }
}

function previous() {
    focus_pos--;

    if (focus_pos < 0) {
        array_pos = array_pos - 5;
        // refresh display
        // check array_pos
        if (array_pos < 0) {
            array_pos = tvshows.length + array_pos;
        }
        display_array = ArrayLookup(array_pos);
        focus_pos = 4;
    }

}

function init() {
    array_pos = 0;
    display_array = ArrayLookup(array_pos);
    focus_pos = 2;
}

init();


function printdata() {
    console.log(array_pos + ":" + display_array[focus_pos]);
    console.log(display_array);
}

for (var i = 0; i < 40; i++) {
    printdata();
    // previous();
    next();
    console.log("\n");
}