Counting sheep...

/*

Consider an array/list of sheep where some sheep may be missing from their place. We need a function that counts the number of sheep present in the array (true means present).

For example,

[true,  true,  true,  false,
  true,  true,  true,  true ,
  true,  false, true,  false,
  true,  false, false, true ,
  true,  true,  true,  true ,
  false, false, true,  true]
The correct answer would be 17.

Hint: Don't forget to check for bad values like null/undefined


*/


export function countSheeps(arrayOfSheep: (boolean | undefined | null)[]) {
  return arrayOfSheep.filter(el=>el === true).length;
}