// return an array with no duplicates

let animals = ['cat', 'dog', 'cat', 'dog'];
let booleans = [true, false, true, false];
let nums = [1,2,1,2];
let mixture = ['cat', true, 1, 'cat', true, 1];


const returnNoDuplicates = (arr) => {
  return arr.reduce((newArr, item) => {
    newArr.find(uniqueItem => uniqueItem === item) === undefined
    ? newArr.push(item)
    : null
    return newArr;
  }, [])
};

console.log(returnNoDuplicates(animals));
console.log(returnNoDuplicates(booleans));
console.log(returnNoDuplicates(nums));
console.log(returnNoDuplicates(mixture));