Function arrayIndexOf

stackgl_modules/index.js:671–720

(arr, val, byteOffset, encoding, dir)

  throw new TypeError('val must be string, number or Buffer');
}
function arrayIndexOf(arr, val, byteOffset, encoding, dir) {
  var indexSize = 1;
  var arrLength = arr.length;
  var valLength = val.length;
  if (encoding !== undefined) {
    encoding = String(encoding).toLowerCase();
    if (encoding === 'ucs2' || encoding === 'ucs-2' || encoding === 'utf16le' || encoding === 'utf-16le') {
      if (arr.length < 2 || val.length < 2) {
        return -1;
      }
      indexSize = 2;
      arrLength /= 2;
      valLength /= 2;
      byteOffset /= 2;
    }
  }
  function read(buf, i) {
    if (indexSize === 1) {
      return buf[i];
    } else {
      return buf.readUInt16BE(i * indexSize);
    }
  }
  var i;
  if (dir) {
    var foundIndex = -1;
    for (i = byteOffset; i < arrLength; i++) {
      if (read(arr, i) === read(val, foundIndex === -1 ? 0 : i - foundIndex)) {
        if (foundIndex === -1) foundIndex = i;
        if (i - foundIndex + 1 === valLength) return foundIndex * indexSize;
      } else {
        if (foundIndex !== -1) i -= i - foundIndex;
        foundIndex = -1;
      }
    }
  } else {
    if (byteOffset + valLength > arrLength) byteOffset = arrLength - valLength;
    for (i = byteOffset; i >= 0; i--) {
      var found = true;
      for (var j = 0; j < valLength; j++) {
        if (read(arr, i + j) !== read(val, j)) {
          found = false;
          break;
        }
      }
      if (found) return i;
    }
  }
  return -1;
}
Buffer.prototype.includes = function includes(val, byteOffset, encoding) {
  return this.indexOf(val, byteOffset, encoding) !== -1;
};