Connect Four

120 minutes


Create a two-player game of Connect Four


  • The board should be 7 wide by 6 high
  • It should alternate between the 'red' and 'yellow' players turn
  • Clicking the "Drop" button should drop a token of the current player's to the bottom-most free position
  • Clicking the "Drop" button on a full column should have no effect
  • If either player gets four in a row (horizontally, vertically, or diagonally):
    • The "COLOR's turn" heading should be replaced by "COLOR won!"
    • The "Drop" buttons should be replaced by a "Play again" button
  • If the board is full and there is no winner:
    • The "COLOR's turn" heading should be replaced by "Draw!"
    • The "Drop" buttons should be replaced by a "Play again" button


  • Checking the win condition is and outside the scope of this question (unless you want the extra challenge!). We have provided a utility to check whether there is a winner or draw. If you are forking a Frontend Eval codepen template, you can access it via window.connectFour.checkForWinner, or you can download it here. Example usage:
// Board must be a 2D array filled with `null` for empty space
// and primitive values representing player tokens (numbers, strings)
// e.g. 1 or 2, 'red' or 'yellow', 'player 1' or 'player 2'
// returns `null` for no winner, 'draw' for draw, or the value of the winning token
const exampleBoard = [
  [1,1,1,1,null,null], // player `1` has 4 in a row

const winner = window.connectFour.checkForWinner(exampleBoard);
console.log(winner); // 1
const clonedBoard = window.connectFour.deepClone(board);

Submitting solutions

  1. Create a solution by forking one of our CodePen templates:
  2. Submit your solution here


Additional challenges

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