diff array of object

diff.js

function diff(col1, col2, predicateFn = a => a) {
  const contains = collection => value =>
    collection.find(item => predicateFn(item) === value);
  const col1Contains = contains(col1);
  const col2Contains = contains(col2);
  return {
    col1: col1.filter(item => !col2Contains(predicateFn(item))),
    col2: col2.filter(item => !col1Contains(predicateFn(item)))
  };
}