Better way to write this JS reduce() code?

Question

the function below simply returns the smallest element in the given array using a reduce function. However, I quickly realized that the code below would throw a TypeError if the given array is empty:

function findSmallestElement(arr) {
  return arr.reduce((a,b) => a < b ? a : b); //throws TypeError if arr is an empty array 
}

So I handled it by throwing in a quick if statement before the reduce() method, as shown below. I'm wondering, is there a more elegant/concise way to do this, given that I must return 0 if the array is empty?

function findSmallestElement(arr) {
  if (arr.length === 0) return 0;
  return arr.reduce((a,b) => a < b ? a : b);
}

Answer 1

You can use the conditional operator and spread into Math.min:

const findSmallestElement = arr => arr.length === 0
  ? 0
  : Math.min(...arr);
console.log(findSmallestElement([1, 2, 3]));
console.log(findSmallestElement([]));

But

given that I must return 0 if the array is empty?

I think this is a mistake, or at least should be considered to be a mistake. An array which is empty does really not have a minimum value. If the array is empty, you might consider returning something other than an ordinary number, something which couldn't be considered to be an ordinary minimum value. It's also unintuitive for, for example, findSmallestElement([-1]) to return -1, but findSmallestElement([]) to return 0.

You might emulate the functionality of Math.min instead, and return Infinity:

const findSmallestElement = arr => Math.min(...arr);
console.log(findSmallestElement([1, 2, 3]));
console.log(findSmallestElement([]));

Or maybe return null. Returning 0 is confusing.