【bug】size is no use in new BitArray(size, hex)

[valaxy]

see code in line 18 in https://github.com/bramstein/bit-array/blob/master/lib/bit-array.js

if (hex.length * 4 > this.length) {
    throw 'Hex value is too large for this bit array.'
} else if (hex.length * 4 < this.length) {
    // pad it
    while(hex.length * 4 < this.length) {
        hex = '0' + hex;
    }
}

what this.length is about? is it undefined?
well, this causes size do nothing when new BitArray(size, hex)

test in chrome, or maybe this is only for nodejs module?