Answer 1

const find = (S, T) => {
  const indexList = [];
  if(S.length < T.length) return -1;
  for(let i = 0; i <= S.length - T.length; i++) {
    if(S.slice(i, i + T.length) === T) indexList.push(i)
   }
  return indexList.length? indexList : -1;
}