js version of https://www.onlinegdb.com/fork/S19tQ06GI

sentencize.js

function is_ascii(str) {
  return /^[\x00-\x7F]*$/.test(str);
}

function is_seperator(c) {
  return [" ", "，", "。", ",", ";", ",", "?", ".", "？", "；", "《", "》"].indexOf(c) > -1;
}

function random_choice(arr) {
    return arr[Math.floor(arr.length * Math.random())];
}

function random_shuffle(array) {
  var current_index = array.length, temporary_value, random_index;

  // While there remain elements to shuffle...
  while (0 !== current_index) {

    // Pick a remaining element...
    random_index = Math.floor(Math.random() * current_index);
    current_index -= 1;

    // And swap it with the current element.
    temporary_value = array[current_index];
    array[current_index] = array[random_index];
    array[random_index] = temporary_value;
  }

  return array;
}

function tokenize(src_txt) {
  var token_list = [];
  var token = "";
  
  for (var c of src_txt) {
    if (is_ascii(c)) {
      token += c;
    } else {
      if (token !== "") {
        token_list.push(token);
        token = "";
      }
      token_list.push(c);
    }
  }
  
  if (token !== "") {
    token_list.push(token);
  }
  
  return token_list;
}

function reorder(token_list) {
  var n_grams = [2, 3];
  var i = 0;
  var token_list_reordered = [];
  
  while (i < token_list.length) {
    var n_gram = random_choice(n_grams);
    var j = Math.min(i + n_gram, token_list.length);

    n_gram = token_list.slice(i, j);
    random_shuffle(n_gram);
    Array.prototype.push.apply(token_list_reordered, n_gram);
    i = j;
  }
  
  return token_list_reordered;
}

function sentencize(src_txt) {
  var sentence_list = [];
  var sentence = "";
  var reordered_txt = [];
  
  for (var c of src_txt) {
    if (is_seperator(c) || !Number.isNaN(+c)) {
      Array.prototype.push.apply(reordered_txt, reorder(tokenize(sentence)));
      reordered_txt.push(c);
      sentence = "";
    } else {
      sentence += c;
    }
  }
  
  if (sentence !== "") {
    Array.prototype.push.apply(reordered_txt, reorder(tokenize(sentence)));
  }
  
  return reordered_txt.join("");
}