Webworker for a recursive function

I have already some elements for my answer, coming from an old post (Trying to implement inline Webworker for a recursive function).

Now I take over this little code implying this issue. This little code uses inline webworkers since I use a recursive function which computes the best hit to play (this is the "computer" Hit). If I don't use webworker and I take a depth too high, the game is hanging in browser.

the source of code is available on this link

I would like to get a working code. Indeed, I am near to the solution since several bugs have been fixed (for example, the fact to include different functions in webworker to make it do its computations without calling external functions. If I don't include all necessary functions, the webworker will not be able to work since it has its own scope.

So I would like to get help to debug my current version.

The game is available on this link I am interested only into "computer vs player" mode (black begins to play). Here below you can find the part when I call the recursive function.

Once computation is done with this recursive function, I would like to get back the object representing the current map of game (positions of black/white circles).

To get back the object or the coordinates suggested for hit (Here we are in main function), I did the following code :

// Call the recursive function and get final (a,b) results
    new Promise( resolve => {
        let HitTemp = JSON.parse(JSON.stringify(HitCurrent));
        let firstWorker = new Worker( workerScript );
        firstWorker.onmessage = function ( event ) {
            resolve( event.data ); //{ result: XXX }
            console.log('here5');
        }
        firstWorker.postMessage([HitTemp, HitTemp.playerCurrent, maxNodes]);
    } ).then( ( { result } ) => {
        //let [ a, b ] = result.coordPlayable;
        let [ a, b ] = HitTemp.coordPlayable;
        console.log('result3 : ', result);
        console.log('here3 : ', a, b);
    } );

  // HERE I TRY TO USE a and b in exploreHitLine function
  // who needs the variables a and b BUT I DON'T KNOW
  // IF a AND b ARE KNOWN HERE FROM CODE ABOVE

  for (k = 0; k < 8; k++) {
   exploreHitLine(HitCurrent, a, b, k, 'drawing');
  }

and below the recursive function (inside inline webworker part) :

window.onload = function() {

  // Inline webworker version
  workerScript = URL.createObjectURL( new Blob( [ `
  "use strict";

...
...
// All other variables and functions necessary for inline webworker
...
...
...


        function negaMax(HitCurrent, colorCurrent, depth) {
          // Indices
          var i, j, k;
          // Evaluation
          var arrayTemp, evalFinal, e;
          // Set current color to HitCurrent
          HitCurrent.playerCurrent = colorCurrent;
          // Deep copy of arrayCurrent array
          arrayTemp = JSON.parse(JSON.stringify(HitCurrent.arrayCurrent));
          // If depth equal to 0
          if (depth == 0)
            return evaluation(HitCurrent);
          // Starting evaluation
          evalFinal = -infinity;
          // Compute all playable hits and check if playable hits
          if (computeHit(HitCurrent, 'playable')) {
            // Browse all possible hits
            for (i = 0; i < 8; i++)
              for (j = 0; j < 8; j++)
            if (HitCurrent.arrayPlayable[i][j] == 'playable') {
              for (k = 0; k < 8; k++) {
                // Explore line started from (i,j) with direction "k"
                exploreHitLine(HitCurrent, i, j, k, 'drawing');
              }
              // Recursive call
              e = -negaMax(JSON.parse(JSON.stringify(HitCurrent)), ((JSON.stringify(HitCurrent.playerCurrent) == JSON.stringify(playerBlack)) ? playerWhite : playerBlack), depth-1);
              if (e > evalFinal) {
                HitCurrent.coordPlayable = [i,j];
                evalFinal = e;
              }
              if (e == -infinity) {
                HitCurrent.coordPlayable = [i,j];
              }
              // Restore arrayCurrent array
              HitCurrent.arrayCurrent = JSON.parse(JSON.stringify(arrayTemp));
            }
            // Clean playable hits once double loop is done
            cleanHits('playable', HitCurrent);
          }
              console.log('here2 :', evalFinal);
          return evalFinal;
             }
        onmessage = function ( event ) {
          let params = event.data;
          //postMessage( { result: recursiveFunction(  HitCurrent, HitCurrent.playerCurrent, maxNodes ) } );
          postMessage( { result: negaMax( ...params ) } );
        };
        ` ], { type: "plain/text" } ) );

     main();
    }

I expect to get back the coordinates "a" and "b" of computed value by recursive function but it seems to return nothing.

I don't know how to receive the object HitTemp object or more directly get a and b suggested coordinates ?

Feel free to ask me more precisions if you don't understand my problem in this algorithm.

from Webworker for a recursive function