JavaScript Taskbook Level 3.10

Задание 1

Given an array, make each element in it repeat twice.

Задание 2

Given an array and a number, leave in the array only those numbers that are divisors of the given number.

Задание 3

Given two numbers, get an array of digits that are in both numbers.

Задание 4

Given a number, get an array with the position of all 3 digits in that number, excluding the first and last.

Задание 5

Given an array of numbers, leave the numbers in it that consist of different digits and delete the rest.

Задание 6

Given an array:

javascript[
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9],
]

Merge the elements of this array into one one-dimensional array:

javascript[1, 2, 3, 4, 5, 6, 7, 8, 9]