Split String Without Characters Loss

split-string-without-characters-loss.js

function splitWithoutCharLoss(str, split_p) {
  //console.log('str:', str);
  const splitter = split_p.split('|');
  //console.log('splitter:', splitter);
  let matches = [];
  let regX;
  
  if (splitter[0] && splitter[1]) { regX = new RegExp(splitter[0]+'(?='+splitter[1]+')'); }
  else if (splitter[0] && !splitter[1]) { regX = new RegExp(splitter[0]); }
  else if (!splitter[0] && splitter[1]) { regX = new RegExp(splitter[1]); }
  // single split
  matches.push(regX.exec(str));
  // multiple splits
  let strCopy = (splitter[0]) ? str.substring(matches[0].index + splitter[0].length, str.length) : str.substring(matches[0].index + splitter[1].length, str.length);
  let nextIndex = regX.exec(strCopy);
  while (nextIndex !== null) {
    //console.log('strCopy:', strCopy);
    matches.push(nextIndex);
    strCopy = (splitter[0]) ? strCopy.substring(nextIndex.index + splitter[0].length, strCopy.length) : strCopy.substring(nextIndex.index + splitter[1].length, strCopy.length);
    nextIndex = regX.exec(strCopy);
  }
  //console.log('regX | matches:', regX, '|', matches);
  let split = [];
  for (let i = 0, max = matches.length; i < max; i++) {
    const match = matches[i];
    //console.log('match:', match);
    if (splitter[0] !== '') {
      split.push(match.input.substring(0, match.index + match[0].length));
      if (i === matches.length - 1) {
        //console.log('end reached');
        split.push(match.input.substring(match.index + match[0].length));
      }
    } else {
      if (i !== matches.length - 1) {
        const nextMatch = matches[i + 1];
        if (i === 0 && match.index !== 0) {
          split.push(match.input.substring(0, match.index));
        }
        split.push(match.input.substring(match.index, match.index + match[0].length + nextMatch.index));
      } else {
        //console.log('end reached');
        if (i === 0 && match.index !== 0) {
          split.push(match.input.substring(0, match.index));
        }
        split.push(match.input.substring(match.index));
      }
    }
  }
  return split.filter((item) => item.length > 0);
}

splitWithoutCharLoss("hello world! hello world!", "o|rl") // ["hello wo", "rld! hello wo", "rld!"]
splitWithoutCharLoss("hello world! hello world!", " |") // ["hello ", "world! ", "hello ", "world!"]
splitWithoutCharLoss(" hello world", " |") // [" ", "hello ", "world"]
splitWithoutCharLoss("hello hello hello ", "| ") // ["hello", " hello", " hello", " "]

SplitStringWithoutCharactersLoss.markdown

Split String Without Characters Loss

Splits string similarly to String.split() but without delimiter loss. Uses | as a delimiter. Character sequence to the left of the delimiter specify the ending sequence of the splitted items. Character sequence to the right of the delimiter specify the starting sequence of the splitted items.

A script by V.

License.