rolling average

rollingavg.js

function rollingAverage(samples = 100) {
  const avgHistory = [];
  let avgSum = 0;
  return {
    add(value) {
      avgHistory.push(value);
      avgSum += value;
      if (avgHistory.length > samples) {
        const bye = avgHistory.shift();
        avgSum -= bye;
      }
    },
    get() {
      return avgSum / avgHistory.length;
    },
  };
}