Javascript 从逗号和破折号分隔的给定字符串中查找所有有效的星期几

We have UI editor from which user can select any number of days.
If the user selects continuous days, those are represented by dashes or hyphens, but if non-continuous days are selected then those are represented by commas..
eg - String - M,W,F - Non Continuous days.
eg - String - M-F - User selected continuous 5 days.

从后台的Angular 来看，如果我们得到一些类似M-Tu,Th,Sa-Su或M-W,F-Su等组合的字符串，如何从中找到有效的天数？

我已经创建了一个常量数组，用于循环或判断值

DAYS: ['M', 'Tu', 'W', 'Th', 'F', 'Sa', 'Su']
let userInput = 'M-Tu,Th,Sa-Su' or 'M-W,F-Su'

SomeMethod(userInput) {
  let validDays = [];
  const commaSeperatedDays = userInput?.split(',');
  const contDaysFromCommaSeparatedDays = commaSeperatedDays.map(x => 
  x.split('-'));
  let indDays = validDays.push(contDaysFromCommaSeparatedDays.map(x => 
  findIndividualDays(x)));

  //When only continuous days are there
  const ContinuousDays = days?.split('-');
}

function findIndividualDays(days) {
//getting confused here how to handle cases - if there is any inbuilt library ?
        if (days.length === 1) {
            return days[0];
        }
        let indDays = [];
        const startIndex = constants.DAYS.indexOf(days[0]);
        const endIndex = constants.DAYS.indexOf(days[1]);
        for (let index = startIndex; index <= endIndex; index++) {
            const element = constants.DAYS[index];
            indDays.push(element);
        }
        return { ...indDays };
    }