JS compact ring buffer useful for logs

ringbuffer.js

// basically https://stackoverflow.com/a/4774081/32164693
function createRingBuffer(length){

  let   pointer = 0;
  const buffer  = []; 

  return {
    get(key){return buffer[key];},
    push(item){
      buffer[pointer] = item;
      pointer = (length + pointer +1) % length;
    }
  };
};

if you need to support concurrent SPSC: ringbuf.js, but where both operations are done in the same thread (as is the case when using a web worker to process logs), the above is sufficient.