sentence.js

function createSentenceArray(str) {
  const arr = str.split(" ");
  const newArr = [];
  
  for (let index = 0; index < arr.length; index++) {
    const word = arr[index];
    
    if (DO_YOUR_REGEX_THING) {
      // if it is a mention push a span
      newArr.push(<span>{word}</span>)
    } else {
      // if it isnt a mention comcatenate the last word 
      // we looped over add the next word to it
      newArr(newArr[newArr.length] + " " + word)
    }
  }

  return newArr;
}