Exhaustive all cases of filling A, B, C, D in to a ten elements array.

abcd.js

function output(intIn) {
    strIn   = intIn.toString(4);
    var aL  = ['A', 'B', 'C', 'D'];
    var msk = '0000000000';
    var len = msk.length;
    var str = msk + strIn;
    var rtn = '';
    str = str.substr(str.length - len, len);
    arr = str.split('');
    for (var i in arr) {
        rtn += aL[arr[i]];
    }
    console.log(rtn);
}

var max = Math.pow(4, 10);

for (var i = 0; i < max; i++) {
    output(i);
}