先声明一个长度12，元素都是null 的数据，再循环obj 的key

[AwangXuan]

let sele = { 1: 222, 2: 123, 5: 888 }
function tansformSele(obj) {
let res = [null, null, null, null, null, null, null, null, null, null, null, null]
for (const [key, value] of Object.entries(obj)) {
res[key - 1] = value
}
return res
}
sele = tansformSele(sele)
console.log("结果:", sele); // (12) [222, 123, null, null, 888, null, null, null, null, null, null, null]

[Stephen-Kai]

let sele = { 1: 222, 2: 123, 5: 888 };
function tansformSele(obj) {
  obj.length = 13;
  let res = Array.from(obj).map((d) => {
    if (!d) {
      return null;
    } else {
      return d;
    }
  });
  res.shift();
  return res;
}
sele = tansformSele(sele);
console.log("结果:", sele); // (12) [222, 123, null, null, 888, null, null, null, null, null, null, null]