n8n.io Function - Smart text truncate for tweets

n8n-function-truncate.js

let MAX_TWEET_LENGTH = 270;

function naiveCut(str, maxLen){
  // Guard
  if (str.length <= maxLen) {
    return str;
  }
  return str.slice(0, maxLen-1);
}

function smartCut(str, maxLen, minAmount) {
  // Guard
  if (str.length <= maxLen) {
    return str;
  }
  
  let strBackup = str;
  let amount;
  
  while(str.length > maxLen) {
    // remove last word
    str = str.replace(/ [^ ]+$/,'');
    // remove trailing whitespace
    str = str.replace(/ +$/,'')  
    amount = str.length / maxLen;
  }
  if (amount > minAmount) {
    return str;
  }
  return strBackup
}


for (item of items) {
  tweet = item.json.contentSnippet;

  newTweet = naiveCut(smartCut(tweet, MAX_TWEET_LENGTH, 0.7), MAX_TWEET_LENGTH);
  // add ellipsis if needed
  if (newTweet != tweet) {
    tweet = tweet + " [...]";
  }
  
  item.json.contentSnippet = tweet;
}

return items;