How to achieve custom sort in primeng

I am having a data like below in the p-table column

SUN - 1, SUN - 2, ... SUN - 11, SUN - 12,

While doing sort it is behaving abnormal. It is not sorting based on number after dash. How to achieve sorting with this format.

I tried to add custom sort

.html <p-table sortFunction)="customSort($event)" [customSort]="true"></p-table>

.ts

    customSort(event: SortEvent) {
       event.data.sort((data1, data2) => {

        let value1 = data1[event.field];

        let value2 = data2[event.field];

        let result = null;

        if (value1 == null && value2 != null)
            result = -1;
        else if (value1 != null && value2 == null)
            result = 1;
        else if (value1 == null && value2 == null)
            result = 0;
        else if (typeof value1 === 'string' && typeof value2 === 'string')
            result = value1.localeCompare(value2);
        else
            result = (value1 < value2) ? -1 : (value1 > value2) ? 1 : 0;

        return (event.order * result);
    });
   }

Here I link stacblitz code for similar issue: https://stackblitz.com/edit/primeng-tablesort-demo-rfn6zn?file=src%2Fapp%2Fproductservice.ts,src%2Fassets%2Fproducts-small.json

You can extract the number value, then do the compare when the values contain SUN. Please check the below code.

  sortTableData(event) {
    console.log(event);
    event.data.sort((data1, data2) => {
      let value1 = data1[event.field];
      let value2 = data2[event.field];
      let result = null;
      if (value1 == null && value2 != null) {
        result = -1;
      } else if (value1 != null && value2 == null) {
        result = 1;
      } else if (value1 == null && value2 == null) {
        result = 0;
      } else if (typeof value1 === 'string' && typeof value2 === 'string') {
        if (value1.includes('SUN') && value2.includes('SUN')) {
          const leftSplit = value1.split(' - ');
          const rightSplit = value2.split(' - ');
          const left = leftSplit.length ? +leftSplit[1] : 0,
            right = rightSplit.length ? +rightSplit[1] : 0;
          result = left < right ? -1 : left > right ? 1 : 0;
        } else {
          result = value1.localeCompare(value2);
        }
      } else {
        result = value1.localeCompare(value2);
      }
      return event.order * result;
    });
  }

stackblitz