const encode = bitstr => {
const bytes = [];
// convert bit string to BigInt
let value = BigInt('0b' + bitstr);
// chop it up into bytes
while (value > 0n) {
bytes.unshift(Number(value & 0xffn));
value >>= 8n;
}
// convert to binary string and encode as base64
return btoa(String.fromCharCode.apply(null, bytes));
};
const decode = b64 => {
// decode base64 to binary string
const bstr = atob(b64);
// convert binary string to bit string
return new Array(bstr.length).fill(0).map(
(_,i) => bstr.charCodeAt(i).toString(2).padStart(8, i ? '0' : '')
).join('');
};
const bitstr = '100110110101000110100011011001100010110100011011001100100110100011000001100000110000011000001100001001010100111110000011001111100101010011111010011100010110001001001001100000110100111010010100111110000111001000100000110001001000101100111110011001001001101011010001011001001101001010000011000100100100110000011010011';
const encoded = encode(bitstr);
const decoded = decode(encoded);
console.log(bitstr);
console.log(encoded);
console.log(decoded);
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