Function bidirectionalIndexOf

lib/buffer.js:1041–1084

(buffer, val, byteOffset, end, encoding, dir)

// - encoding - an optional encoding, relevant if val is a string
// - dir - true for indexOf, false for lastIndexOf
function bidirectionalIndexOf(buffer, val, byteOffset, end, encoding, dir) {
  validateBuffer(buffer);

  if (typeof byteOffset === 'string') {
    encoding = byteOffset;
    byteOffset = undefined;
  } else if (byteOffset > 0x7fffffff) {
    byteOffset = 0x7fffffff;
  } else if (byteOffset < -0x80000000) {
    byteOffset = -0x80000000;
  }
  // Coerce to Number. Values like null and [] become 0.
  byteOffset = +byteOffset;
  // If the offset is undefined, "foo", {}, coerces to NaN, search whole buffer.
  if (NumberIsNaN(byteOffset)) {
    byteOffset = dir ? 0 : (buffer.length || buffer.byteLength);
  }
  dir = !!dir;  // Cast to bool.

  if (typeof val === 'number')
    return indexOfNumber(buffer, val >>> 0, byteOffset, dir, end);

  let ops;
  if (encoding === undefined)
    ops = encodingOps.utf8;
  else
    ops = getEncodingOps(encoding);

  if (typeof val === 'string') {
    if (ops === undefined)
      throw new ERR_UNKNOWN_ENCODING(encoding);
    return ops.indexOf(buffer, val, byteOffset, dir, end);
  }

  if (isUint8Array(val)) {
    const encodingVal =
      (ops === undefined ? encodingsMap.utf8 : ops.encodingVal);
    return indexOfBuffer(buffer, val, byteOffset, encodingVal, dir, end);
  }

  throw new ERR_INVALID_ARG_TYPE(
    'value', ['number', 'string', 'Buffer', 'Uint8Array'], val,
  );
}

Buffer.prototype.indexOf = function indexOf(val, offset, end, encoding) {
  if (typeof end === 'string') {