Average of numbers

Calculates the average of two or more numbers.

• Use Array.prototype.reduce() to add each value to an accumulator, initialized with a value of 0.
• Divide the resulting array by its length.

const average = (...nums) =>
  nums.reduce((acc, val) => acc + val, 0) / nums.length;

average(...[1, 2, 3]); // 2
average(1, 2, 3); // 2