product-of-array-except-self.js

const productExceptSelf = (nums) => {
  const result = new Array(nums.length).fill(1);

  let prefix = 1;
  for (let i = 0; i < nums.length; i++) {
    result[i] = prefix;
    prefix *= nums[i];
  }

  let postfix = 1;
  for (let i = nums.length - 1; i >= 0; i--) {
    result[i] *= postfix;
    postfix *= nums[i];
  }

  return result;
};