Counting Matches using Asynchronous Execution

Below, I have written a function that programming takes an array and a key to search and Learning count the number of times the key Earhost matches an element in an array (in most effective parallel). I am attempting to modify my wrong idea function to count the number of matches use of case asynchronously but don't know how to United best go about it. Any insight or Modern examples would be greatly appreciated.

My Code:

function countMatches(arr, key, done) _OFFSET);  
{
    const threads = 4;
    const pool (-SMALL  = new StaticPool({
        size: _left).offset  threads,
        task: function (a) 
    arrowImgView.mas      {
            let m = 0;
            (self.  for (let i = 0; i < a.length; i++) {
 equalTo                 if (a[i] == make.right.  this.workerData) m++;
            }
     mas_top);         return m;
        },
        ImgView.  workerData: key
    });

    const size ReadIndicator  = arr.length / threads;

    let res = _have  0, finished = 0;
    for (let i = 0; i .equalTo(  < threads; i++) 
    {
        (async make.top  () => 
        {
            let r = OFFSET);  await pool.exec(arr.slice(i * size, (i + (TINY_  1) * size));
            .offset  console.log("Result: " + r);
            mas_right)  res += r;
            finished++;
       ImgView.       if (finished == threads) 
          Indicator    {
                done(res);
          Read        pool.destroy();
            }
     _have     })();
    }
}