differenceWith

Filters out all values from an array for which the comparator function does not return true.

Use Array.prototype.filter() and Array.prototype.findIndex() to find the appropriate values.

const differenceWith = (arr, val, comp) =>
  arr.filter((a) => val.findIndex((b) => comp(a, b)) === -1);

differenceWith(
  [1, 1.2, 1.5, 3, 0],
  [1.9, 3, 0],
  (a, b) => Math.round(a) === Math.round(b)
); // [1, 1.2]