Code for making decisions off of binary values

binaryDecisions.js

function bd(binaryString) {
    return parseInt(binaryString, 2);
}
function db(num) {
   return num.toString(2);
}
function rl(binaryString,l) {
    var zeros = "";
    for (var i = 0; i < l - binaryString.length; i++) {
        zeros += "0";
    }
    return zeros + binaryString;
}

function overlayBitMask_and(a,b,c) {
    var r = [];
    if (a.length == b.length && b.length == c.length) {
        throw new Error("OverlayBitMaskThe length of all three parameters must be the same.");
    }
    rl(db(bd(a) & bd(b)), a.length)
    .split('')
    .forEach(
        (bit,i) => bit == '1' ? r.push(c[i]) : null
    );
    return r;
}
function overlayBitMask_or(a,b,c) {
    var r = [];
    if (a.length == b.length && b.length == c.length) {
        throw new Error("OverlayBitMaskThe length of all three parameters must be the same.");
    }
    rl(db(bd(a) | bd(b)), a.length)
    .split('')
    .forEach(
        (bit,i) => bit == '1' ? r.push(c[i]) : null
    );
    return r;
}
function overlayBitMask_xor(a,b,c) {
    var r = [];
    if (a.length == b.length && b.length == c.length) {
        throw new Error("OverlayBitMaskThe length of all three parameters must be the same.");
    }
    rl(db(bd(a) ^ bd(b)), a.length)
    .split('')
    .forEach(
        (bit,i) => bit == '1' ? r.push(c[i]) : null
    );
    return r;
}