How to sort based on incomplete criteria?

Question

First I tried passing my own function to Array.sort, but it doesn\'t sort correctly. Notice how \'c\' comes before \'a\' in the resul

Answer 1

Maybe something like this

const sorted = ['a', 'b', 'c', 'd']; // I do NOT have access to this
const unsorted = ['c', 'd', 'a', 'b'];

const a_before_b = (a, b) => {
  if (a == 'a' && b == 'd') return true;
  if (a == 'b' && b == 'c') return true;
  if (a == 'a' && b == 'c') return true;

}

const b_before_a = (a, b) => {
  if (b == 'a' && a == 'c') return true;
  if (b == 'b' && a == 'c') return true;
}

const mySortingFunction = (a, b) => {
  if (a_before_b(a, b)) return -1;
  if (b_before_a(a, b)) return 1;
  return 0;
}

// doesn't produce correct sorting 
console.log(unsorted.sort(mySortingFunction));