const parseTweet = function()

in js/src/parseTweet.js [30:83]
45 lines of code
15 McCabe index (conditional complexity)

const parseTweet = function(text = '', options = configs.defaults) {
  const mergedOptions = Object.keys(options).length ? options : configs.defaults;
  const { defaultWeight, emojiParsingEnabled, scale, maxWeightedTweetLength, transformedURLLength } = mergedOptions;
  const normalizedText = typeof String.prototype.normalize === 'function' ? text.normalize() : text;

  // Hash all entities by their startIndex for fast lookup
  const urlEntitiesMap = transformEntitiesToHash(extractUrlsWithIndices(normalizedText));
  const emojiEntitiesMap = emojiParsingEnabled ? transformEntitiesToHash(extractEmojiWithIndices(normalizedText)) : [];
  const tweetLength = normalizedText.length;

  let weightedLength = 0;
  let validDisplayIndex = 0;
  let valid = true;
  // Go through every character and calculate weight
  for (let charIndex = 0; charIndex < tweetLength; charIndex++) {
    // If a url begins at the specified index handle, add constant length
    if (urlEntitiesMap[charIndex]) {
      const { url, indices } = urlEntitiesMap[charIndex];
      weightedLength += transformedURLLength * scale;
      charIndex += url.length - 1;
    } else if (emojiParsingEnabled && emojiEntitiesMap[charIndex]) {
      const { text: emoji, indices } = emojiEntitiesMap[charIndex];
      weightedLength += defaultWeight;
      charIndex += emoji.length - 1;
    } else {
      charIndex += isSurrogatePair(normalizedText, charIndex) ? 1 : 0;
      weightedLength += getCharacterWeight(normalizedText.charAt(charIndex), mergedOptions);
    }

    // Only test for validity of character if it is still valid
    if (valid) {
      valid = !hasInvalidCharacters(normalizedText.substring(charIndex, charIndex + 1));
    }
    if (valid && weightedLength <= maxWeightedTweetLength * scale) {
      validDisplayIndex = charIndex;
    }
  }

  weightedLength = weightedLength / scale;
  valid = valid && weightedLength > 0 && weightedLength <= maxWeightedTweetLength;
  const permillage = Math.floor((weightedLength / maxWeightedTweetLength) * 1000);
  const normalizationOffset = text.length - normalizedText.length;
  validDisplayIndex += normalizationOffset;

  return {
    weightedLength,
    valid,
    permillage,
    validRangeStart: 0,
    validRangeEnd: validDisplayIndex,
    displayRangeStart: 0,
    displayRangeEnd: text.length > 0 ? text.length - 1 : 0
  };
};