tic tac toe using html 2c javascript and css

1const player = "O";
2const computer = "X";
3
4let board_full = false;
5let play_board = ["", "", "", "", "", "", "", "", ""];
6
7const board_container = document.querySelector(".play-area");
8
9const winner_statement = document.getElementById("winner");
10
11check_board_complete = () => {
12  let flag = true;
13  play_board.forEach(element => {
14    if (element != player && element != computer) {
15      flag = false;
16    }
17  });
18  board_full = flag;
19};
20
21const check_line = (a, b, c) => {
22  return (
23    play_board[a] == play_board[b] &&
24    play_board[b] == play_board[c] &&
25    (play_board[a] == player || play_board[a] == computer)
26  );
27};
28
29const check_match = () => {
30  for (i = 0; i < 9; i += 3) {
31    if (check_line(i, i + 1, i + 2)) {
32      return play_board[i];
33    }
34  }
35  for (i = 0; i < 3; i++) {
36    if (check_line(i, i + 3, i + 6)) {
37      return play_board[i];
38    }
39  }
40  if (check_line(0, 4, 8)) {
41    return play_board[0];
42  }
43  if (check_line(2, 4, 6)) {
44    return play_board[2];
45  }
46  return "";
47};
48
49const check_for_winner = () => {
50  let res = check_match()
51  if (res == player) {
52    winner.innerText = "Winner is player!!";
53    winner.classList.add("playerWin");
54    board_full = true
55  } else if (res == computer) {
56    winner.innerText = "Winner is computer";
57    winner.classList.add("computerWin");
58    board_full = true
59  } else if (board_full) {
60    winner.innerText = "Draw!";
61    winner.classList.add("draw");
62  }
63};
64
65const render_board = () => {
66  board_container.innerHTML = ""
67  play_board.forEach((e, i) => {
68    board_container.innerHTML += `<div id="block_${i}" class="block" onclick="addPlayerMove(${i})">${play_board[i]}</div>`
69    if (e == player || e == computer) {
70      document.querySelector(`#block_${i}`).classList.add("occupied");
71    }
72  });
73};
74
75const game_loop = () => {
76  render_board();
77  check_board_complete();
78  check_for_winner();
79}
80
81const addPlayerMove = e => {
82  if (!board_full && play_board[e] == "") {
83    play_board[e] = player;
84    game_loop();
85    addComputerMove();
86  }
87};
88
89const addComputerMove = () => {
90  if (!board_full) {
91    do {
92      selected = Math.floor(Math.random() * 9);
93    } while (play_board[selected] != "");
94    play_board[selected] = computer;
95    game_loop();
96  }
97};
98
99const reset_board = () => {
100  play_board = ["", "", "", "", "", "", "", "", ""];
101  board_full = false;
102  winner.classList.remove("playerWin");
103  winner.classList.remove("computerWin");
104  winner.classList.remove("draw");
105  winner.innerText = "";
106  render_board();
107};
108
109//initial render
110render_board();
111