Variable Integer (LEB128) encoding with BigInt

varint.js

export function encode(value) {
  const long = BigInt(value);
  const result = [];

  let shift = 0n;
  while (true) {
    const number = Number(BigInt.asUintN(7, long >> shift));
    if (number) {
      result.push(number);
      shift += 7n;
    } else {
      break;
    }
  }

  for (let i = 0, len = result.length - 1; i < len; i++) {
    result[i] += 128;
  }

  return new Uint8Array(result);
}