Amicable Numbers. Números amigos

amicable.js

function sumProperDivisors(num) {
  return [...Array(Math.floor(num / 2))].reduce((acc,v, ind) =>  (num % (ind + 1)) === 0 ? (acc + ind + 1) : acc, 0)
}
function areAmicableNumbers(num1, num2) {
  return sumProperDivisors(num1) === num2 && sumProperDivisors(num2) === num1
}
function amicableNumbersInRange(start,end){
  let nums = [...Array(Number.parseInt((end - start) / 2))].map((v,i)=>start+i);
 return [...nums.reduce((acc, v, i) => {
    const possibleAmical = sumProperDivisors(v);
   return !acc.has(possibleAmical) && areAmicableNumbers(v, possibleAmical) ? acc.set(v, possibleAmical) : acc;
  },new Map()).entries()]
}
console.log(areAmicableNumbers(220,284))
let amicableFrom200to1300 = amicableNumbersInRange(200,1300)
console.log(amicableFrom200to1300)

Version without input checking