Robust Code with explanation
Intuition\nThe reduce function is used to apply a given function to each element of an array and return a single accumulated value.\n\n# Approach\n- Check if th
# Intuition\nThe **reduce** function is used to apply a given function to each element of an array and return a single accumulated value.\n\n# Approach\n- Check if the input array is empty. If it is, return the initial value.\n- If an initial value is provided, set the accumulator to the initial value. Otherwise, set it to the first element of the array.\n- Determine the starting index for the loop based on whether an initial value was provided. If an initial value was provided, start the loop at index 0. Otherwise, start at index 1.\n- Iterate over the input array using a simple for loop starting at the determined starting index.\n- Apply the given function to the accumulator and the current element of the array, and update the accumulator with the result.\n- Once all elements of the array have been processed, return the final accumulated value.\n\n# Complexity\n- Time complexity: O(n)\n\n- Space complexity: O(1)\n\n# Code\n```\n/**\n * @param {number[]} nums\n * @param {Function} fn\n * @param {number} init\n * @return {number}\n */\nvar reduce = function(nums, fn, init) {\n    // Return init value if array is empty\n    if (nums.length === 0) return init;\n\n    // If init value is undefine then first item in the array is assigned\n    let accumilate = init ?? nums[0];\n\n    // If first item of the the array is assigned, then start count from 1 if not 0\n    let start = (accumilate === init) ? 0 : 1;\n\n    // Simple for loop\n    for (let i = start; i < nums.length; i++) {\n        accumilate = fn(accumilate, nums[i]);\n    }\n\n    return accumilate;\n};\n```
['Array', 'JavaScript']