Problem

Given an array of integers, write a function that returns the sum of the elements in the array.
Example input: [1, 2, 3, 4, 5]
Example output: 15

Solution

// Solution:

function sum(arr) {
  return arr.reduce((acc, curr) => acc + curr, 0);
}

// Explanation:
// The reduce method is the most optimal solution because it is a built-in method that iterates over an array and returns a single value.
// The reduce method takes a callback function as an argument. The callback function takes two arguments, the accumulator and the current value.
// The accumulator is the value that is returned from the callback function. The current value is the current element in the array.
// The reduce method also takes an optional second argument, which is the initial value of the accumulator.
// In this case, the initial value of the accumulator is 0.
// The callback function adds the current value to the accumulator and returns the accumulator.
// The reduce method iterates over the array and returns the accumulator, which is the sum of the elements in the array.