averageFilter.js

let avg = 0;
const numbers = [];

function average (numbers = []) {
  const sum = numbers.reduce((prev, current) => prev + current, 0);
  return sum/numbers.length;
}
console.time('avg1');
for (let i = 1; i < 100001; i++) {
  numbers.push(i);
  avg = average(numbers);
}
console.timeEnd('avg1');
console.log(`그래서 평균은? -> ${avg}`);

let avg2 = 0;
function cumulativeAverage (prevAvg, newNumber, listLength) {
  const oldWeight = (listLength - 1) / listLength;
  const newWeight = 1 / listLength;
  return (prevAvg * oldWeight) + (newNumber * newWeight);
}

console.time('avg2');
for (let i = 1; i < 1000001; i++) {
  avg2 = cumulativeAverage(avg2, i, i);
}
console.timeEnd('avg2');
console.log(`그래서 평균은? -> ${avg2}`);