How to use an object key dynamically in a JavaScript function without the (.) notation?

Question

I'm implementing a sorting function like this.

  const handleSort = (sortBy) => {
    const compareFunction = (a, b) => {
      if (a.medicineName < b.medicineName) {
        return -1;
      }
      if (a.medicineName > b.medicineName) {
        return -1;
      }
      return 0;
    };
    setFilteredMedicineList((prevFilteredMedicineList) => {
      const copyOfPrevFilteredMedicineList = [...prevFilteredMedicineList];
      copyOfPrevFilteredMedicineList.sort(compareFunction);
      return copyOfPrevFilteredMedicineList;
    });
  };

I have an array of objects like this. The objects are the ones being sorted.

const myArray = [
    {
      medicineName: "Abcdefgh",
      medicineId: 1,
    },
    {
      medicineName: "Another name",
      medicineId: 2,
    },
  ];

I have a button that calls the handleSort function on click. Now my current compare function has the "medicine name" hardcoded. I want the function to be dynamic in that it uses the sortBy parameter to do the comparison. I know I can write another function for each case but I'm trying to force myself to write "clean code" to avoid what a friend told me is "smelly code". How can I implement something like this

 const compareFunction = (a, b) => {
      if (a.sortBy< b.sortBy) {
        return -1;
      }
      if (a.sortBy > b.sortBy) {
        return -1;
      }
      return 0;
    };

I want in a way if I pass "medicineId" as a parameter that is what will be used to do the sorting. Note I have tried the above code and it is not doing what you would expect. Please help.