sortedUnion.js

// Write a function that takes two or more arrays and returns a new array of unique values in the order of the original provided arrays.

// In other words, all values present from all arrays should be included in their original order, but with no duplicates in the final array.

// The unique numbers should be sorted by their original order, but the final array should not be sorted in numerical order.

// Check the assertion tests for examples.

function uniteUnique(arr) {

  var newArr = []

  for (var i = 0; i < arguments.length; i++) {
    newArr = newArr.concat(arguments[i]);
  }
  let unique = [... new Set(newArr)]
  
  return unique
}

uniteUnique([1, 3, 2], [5, 2, 1, 4], [2, 1]);

console.log(uniteUnique([1, 2, 3], [5, 2, 1, 4], [2, 1], [6, 7, 8]))