// Finds the first index which is a duplicate value
// Returns -1 if there are no duplicates
// Returns the index of the first duplicate entry it finds

// Note: This "can" fail if the object entries don't have their properties in the
// same order.
export const findDuplicateIndex = (arr: Array<unknown>) => {
  const _uniqSet = new Set();
  let currSetSize = 0;
  for (let i = 0; i < arr.length; i++) {
    // JSON.stringify because value can be objects
    _uniqSet.add(JSON.stringify(arr[i]));
    if (_uniqSet.size > currSetSize) currSetSize = _uniqSet.size;
    else return i;
  }
  return -1;
};