Q.

Description:
Given two arrays of strings a1 and a2 return a sorted array r in lexicographical order of the strings of a1 which are substrings of strings of a2.

Example 1:
a1 = ["arp", "live", "strong"]

a2 = ["lively", "alive", "harp", "sharp", "armstrong"]

returns ["arp", "live", "strong"]

Example 2:
a1 = ["tarp", "mice", "bull"]

a2 = ["lively", "alive", "harp", "sharp", "armstrong"]

returns []

Notes:
Arrays are written in "general" notation. See "Your Test Cases" for examples in your language.
In Shell bash a1 and a2 are strings. The return is a string where words are separated by commas.
Beware: r must be without duplicates.

A)

function inArray(array1,array2){
  //...
  let res = [];
  for (let key of array1) {
    for (let el of array2) {
      if(el.includes(key)) res.push(key)
    }
  }
  res.sort()
  return res.filter((item, index) => res.indexOf(item) === index)
}