function removeDouble(arr) {
	const resultArray = []
	for (let i = 0, length = arr.length; i < length; i++) {
  	const arrOfItems = arr.filter(item => item === arr[i]);
    if (arrOfItems.length === 1) {
    	resultArray.push(arr[i])
    }
  }
  return resultArray
}

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