1const min = arr => Math.min(...arr);

1arr = [11, 10, 10];
2var index = arr.indexOf(Math.max(...arr));

1// Assuming the array is all integers,
2// Math.min works as long as you use the spread operator(...).
3
4let arrayOfIntegers = [9, 4, 5, 6, 3];
5let min = Math.min(...arrayOfIntegers);
6// => 3 
7