maxProfit.js

const maxProfit = (prices = []) => {
  let minPrice = Number.MAX_SAFE_INTEGER;
  let maxProfit = 0;
  
  prices.forEach(price => {
    if (price < minPrice) {
      minPrice = price;
    } else if (price - minPrice > maxProfit) {
      maxProfit = price - minPrice;
    }
  });
  
  return maxProfit;
};

const prices = [7, 1, 5, 6, 3];

console.log('prices', prices);
console.log('maxProfit', maxProfit(prices));