Function encodeVarint

encoding/varint.ts:219–251

(
  num: bigint | number,
  buf: Uint8Array = new Uint8Array(MaxVarintLen64),
  offset = 0,
)

 */
// deno-lint-ignore deno-style-guide/exported-function-args-maximum
export function encodeVarint(
  num: bigint | number,
  buf: Uint8Array = new Uint8Array(MaxVarintLen64),
  offset = 0,
): [Uint8Array_, number] {
  num = BigInt(num);
  if (num < 0n) {
    throw new RangeError(
      `Cannot encode the input into varint as it should be non-negative integer: received ${num}`,
    );
  }
  if (num > MaxUint64) {
    throw new RangeError(
      `Cannot encode the input ${num} into varint as it overflows uint64`,
    );
  }
  for (
    let i = offset;
    i < buf.length;
    i += 1
  ) {
    if (num < MSBN) {
      buf[i] = Number(num);
      i += 1;
      return [buf.slice(offset, i), i];
    }
    buf[i] = Number((num & 0xFFn) | MSBN);
    num >>= SHIFTN;
  }
  throw new RangeError(
    "Cannot encode the input into varint: the provided buffer is too small",
  );
}