解法：

const str = "I am an 20-years out--standing @ * -stu- dent";

function solution(str) {
  const arr = str.split(" ");
  const newArr = arr.map((str) => {
    if (/[a-zA-Z0-9-]/.test(str)) {
      if (/-{2}/g.test(str)) {
        return str.replace(/--/g, " ");
      } else if (str.startsWith("-") || str.endsWith("-")) {
        return str.replace(/-/g, "");
      } else {
        return str;
      }
    } else return "";
  });
  console.log("new", newArr);
  return newArr
    .reverse()
    .filter((item) => item !== "")
    .join(" ");
}

console.log(solution(str));
/* 
 I am an 20-years out--standing @ * -stu- dent =>  dent stu standing out 20-years an am I
 */