CodeWars符号化問題2021/01/29-Sums of Parts

[質問]
Let us consider this example (array written in general format):ls = [0, 1, 3, 6, 10]Its following parts:
ls = [0, 1, 3, 6, 10]
ls = [1, 3, 6, 10]
ls = [3, 6, 10]
ls = [6, 10]
ls = [10]
ls = []
The corresponding sums are (put together in a list): [20, 20, 19, 16, 10, 0]The function parts_sums (or its variants in other languages) will take as parameter a list ls and return a list of the sums of its parts as defined above.
Other Examples:
ls = [1, 2, 3, 4, 5, 6]
parts_sums(ls) -> [21, 20, 18, 15, 11, 6, 0]
ls = [744125, 935, 407, 454, 430, 90, 144, 6710213, 889, 810, 2579358]
parts_sums(ls) -> [10037855, 9293730, 9292795, 9292388, 9291934, 9291504, 9291414, 9291270, 2581057, 2580168, 2579358, 0]
Notes

Some lists can be long.

Please ask before translating: some translations are already written and published when/if the kata is approved.

(要約)所与の配列の合計から最初の要素から最後の要素まで、車の積算値を配列に蓄積します.
[回答]

function partsSums(ls) {
  let sumNum = ls.reduce((acc, num) => acc += num, 0);
  const answer = [sumNum];
  const length = ls.length;

  for(let i = 0; i < length; i++) {
    sumNum -= ls[i];
    answer.push(sumNum);
  }

  return answer;
}

配列の総和を求め,最初の要素として入れ,繰り返し文から配列中pushに前に移動する.
次の2つのロジックがタイムアウトし、テストケースには1万以上の要素があります.popがタイムアウトしたのは理由があると思います.

function partsSums(ls) {
  const answer = [0];

  while(ls.length) {
    const sumNum = answer[0] + ls.pop();
    answer.unshift(sumNum);
  }

  return answer;
}

function partsSums(ls) {
  const answer = [0];
  const length = ls.length - 1;

  for(let i = length; i >= 0; i--) {
    const sumNum = answer[0] + ls.pop();
    answer.unshift(sumNum);
  }

  return answer;
}