Problem 5/30 of LeetCode 30-day challenge

maxProfit.js

let maxProfit = function(prices) {
  // two pointers -- buy & sell
  let buy = 0;
  let sell = 1;
  let buyPrice = 0;
  let sellPrice = 0;
  let price = 0;
  
  while(sell < prices.length) {
    if(prices[buy] < prices[sell]) {
      // if the buy price is less than sell price
      // set the corresponding prices then evaluate 
      // the next value after the current sell price
      buyPrice = prices[buy];
      sellPrice = prices[sell];
      if(sellPrice > prices[sell+1] || prices[sell+1] === undefined){
        // if the current sell price is higher than the next price
        // or if we are at the end of the array
        // complete a transaction
        price += (sellPrice - buyPrice);
        // set buy to the current sell,
        // and sell to the next price
        buy = sell;
        sell = sell + 1;
      } else {
        // if the next price is higher,
        // move the pointer to that price and reevaluate
        sell++;
      }
    } else {
      // else, move the pointers up one position
      buy++;
      sell++;
    }
  }
  return price;
};