best-time-to-buy-and-sell-stock.js

const maxProfit = (prices) => {
  let buy = 0,
    sell = 1,
    max = (profit = 0);

  while (sell < prices.length) {
    if (prices[buy] < prices[sell]) {
      profit = prices[sell] - prices[buy];
      max = Math.max(max, profit);
    } else {
      buy = sell;
    }

    sell++;
  }

  return max;
};