JSFiddle - React, Tailwind, and code Playground

JavaScript 1.7

class RunningMedian {
  minHeap = new MinHeap();
  maxHeap = new MaxHeap();

  add = (val) => {
    maxHeap.add(val);
    minHeap.add(maxHeap.poll());
    if (maxHeap.size() < minHeap.size()) {
      maxHeap.add(minHeap.poll());
    }
  };

  median = () => {
    if (maxHeap.size() > minHeap.size()) {
      return maxHeap.peek();
    }
    return (minHeap.peek() + maxHeap.peek()) / 2;
  }
}