minimax.js

    function minimax(level, player) {


        if (checkWin(player) || level === 0 || checkWin(AI)) {

            score = evaluate();
            return score;

        }



        if (checkWin(human)) {
            //      console.log("1x")   

            return -10;


        } else if (checkWin(AI)) {
            //       console.log("2x")  

            return 10;


        } else if (checkDraw()) {
            console.log("tie");


            return 0;


        } else {






            var moves = validMoves();


            if (player == AI) {


                var bestScore = 100;

                // var alpha = -1;




                for (var i = 0; i < moves.length; i++) {

                    var m = moves[i];
                    copy[m] = AI;


                    // recursive call 
                    var score = minimax(level - 1, human);


                    if (score < bestScore) {

                        bestScore = score;
                        alpha = m;

                        // stop it here if the win condition is met
                        if (checkWin(AI) === true) {

                            copy[m] = "";

                            return [alpha, bestScore];

                        }


                    }



                    copy[m] = "";
                    draw();
                }


                return [alpha, bestScore];

            } else {


                var bestScore = -100;
                //   var alpha = -1;


                for (var x = 0; x < moves.length; x++) {

                    var m = moves[x];
                    copy[m] = human;

                    // recursive call 
                    var score = minimax(level - 1, AI);


                    if (score > bestScore) {

                        bestScore = score;
                        alpha = m;

                    }
                    copy[m] = "";
                    draw();
                }

                return [alpha, bestScore];

            }

        }

    }