Number of Smooth Descent Periods of a Stock.js

// Runtime: 154 ms (Top 25.58%) | Memory: 52.6 MB (Top 62.79%)
var getDescentPeriods = function(prices) {
    const n = prices.length;

    let left = 0;
    let totRes = 0;

    while (left < n) {
        let count = 1;

        let right = left + 1;

        while (right < n && prices[right] + 1 === prices[right - 1]) {
            count += (right - left + 1);
            ++right;
        }

        totRes += count;

        left = right;
    }

    return totRes;
};