unction replaceOneToMany(next) {
  const many = [list[RANGE_START]];
  for (let id = 0; id < RANGE_START; id++)
    many.push({id, text: `R${Math.random()}`});
  list.splice(RANGE_START, 1, ...many);
  console.time('replace-one-to-many');
  $(document.body, ul);
  console.timeEnd('replace-one-to-many');
  next();
}

function replaceManyToOne(next) {
  const li = list[RANGE_START];
  list.splice(RANGE_START, RANGE_START + 1, li);
  console.time('replace-many-to-one');
  $(document.body, ul);
  console.timeEn