Best time to buy and sell stock

var maxProfit = function(prices) {
    const buy = Math.min(prices);                   //finding the lowest value/ buy price
    const index = prices.indexOf(buy);              //get the index of the buy price
    let temp = [];                                  //temporary array to store possible sell prices
    for (let i=index; i<prices.length-1; i++) {
        if (prices[i] > prices[index]) {            //iterate for every element in prices later than buy price
            temp.push(prices[i]);                   //add the values to the temp array
        }
    }
    const sell = Math.max(temp);                    //get the highest value in this temp array
    const profit = sell-buy;                        //get profit 
    if (sell == null) {
        return 0;
    }
    return profit;
};