111_getElementsOfPropertyAtIndex.js

/*
Write a function called "getElementOfArrayProperty".

Given an object, a key, and a numerical index, "getElementOfArrayProperty" returns the value of the element at the given index of the array located within the given object at the given key.

Notes:
* If the array is empty, it should return undefined.
* If the given index is out of range of the array located at the given key, it should return undefined.
* If the property at the given key is not an array, it should return undefined.
* If there is no property at the key, it should return undefined. 


var obj = {
 key: ['Jamil', 'Albrey']
};
var output = getElementOfArrayProperty(obj, 'key', 0); 
console.log(output); // --> 'Jamil'
*/

function getElementOfArrayProperty(obj, key, index) {
  var arr = obj[key];
  if (!Object.keys(obj).includes(key) || arr.length === 0 || index > arr.length - 1 || !Array.isArray(arr)) {
    return undefined;
  } else {
    return arr[index];
  }
}