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HTML 

              
                <div class="h-screen w-screen flex justify-center items-center">
  <canvas id="tetris-canvas" width="420" height="600"></canvas>
</div>
!

CSS
!

JS 

              
                class Game {
  constructor() {
    this.score = 0
    this.boardWidth = 10
    this.boardHeight = 23
    this.currentBoard = new Array(this.boardHeight).fill(0).map(() => new Array(this.boardWidth).fill(0))
    this.landedBoard = new Array(this.boardHeight).fill(0).map(() => new Array(this.boardWidth).fill(0))
    this.currentTetromino = this.randomTetromino()
    this.canvas = document.getElementById('tetris-canvas')
    this.ctx = this.canvas.getContext('2d')
    this.gameInterval = null
    this.gameOver = false
  }

  draw(blockSize = 24, padding = 4) {
    /* Vẽ khung của board */
    this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);
    this.ctx.lineWidth = 2
    this.ctx.rect(padding, padding, blockSize * this.boardWidth + padding * (this.boardWidth + 1), blockSize * (this.boardHeight - 3) + padding * (this.boardHeight - 3 + 1))
    this.ctx.stroke()

    /* Lặp qua các phần tử của mảng board và vẽ các block tại đúng vị trí */
    for (let i = 3; i < this.boardHeight; i++) {
      for (let j = 0; j < this.boardWidth; j++) {
        if (this.currentBoard[i][j] > 0) {
          this.ctx.fillStyle = this.getColor(this.currentBoard[i][j])
        } else {
          this.ctx.fillStyle = 'rgb(248, 248, 248)'
        }
        this.ctx.fillRect(padding * 2 + j * (blockSize + padding), padding * 2 + (i - 3) * (blockSize + padding), blockSize, blockSize)
      }
    }

    /* Viết ra các đoạn text */
    this.ctx.fillStyle = 'rgb(0, 0, 0)'
    this.ctx.font = '28px';
    this.ctx.fillText('TIẾP THEO:', 300, 28)
    this.ctx.fillText('ĐIỂM SỐ:', 300, 200)
    this.ctx.fillText(this.score.toString(), 300, 230)
  }
  
  getColor(cellNumber) {
    switch (cellNumber) {
      case 1:
        return LShape.color
      case 2:
        return JShape.color
      case 3:
        return OShape.color
      case 4:
        return TShape.color
      case 5:
        return SShape.color
      case 6:
        return ZShape.color
      case 7:
        return IShape.color
    }
  }

  randomTetromino() {
    const randNum = Math.floor(Math.random() * Math.floor(7))
    switch (randNum) {
      case 0:
        return new LShape(1, 4)
      case 1:
        return new JShape(1, 4)
      case 2:
        return new OShape(2, 4)
      case 3:
        return new TShape(2, 4)
      case 4:
        return new SShape(2, 4)
      case 5:
        return new ZShape(2, 4)
      case 6:
        return new IShape(0, 4)
    }
  }

  play() {
    this.gameInterval = setInterval(() => {
      this.progress()
      this.updateCurrentBoard()
      this.draw()
    }, 800);
  }

  progress() {
    let nextTetromino = new this.currentTetromino.constructor(this.currentTetromino.row + 1, this.currentTetromino.col, this.currentTetromino.angle)
    if (!this.bottomOverlapped(nextTetromino) && !this.landedOverlapped(nextTetromino)) {
      this.currentTetromino.fall()
    } else {
      this.mergeCurrentTetromino()
      
      const clearableRowIndexes = this.findClearableRows()
      this.clearRows(clearableRowIndexes)
      this.score += this.calculateScore(clearableRowIndexes.length)
      if (this.isGameOver()) {
        clearInterval(this.gameInterval)
        this.gameOver = true
      }
      
      this.currentTetromino = this.randomTetromino()
    }
  }

  leftOverlapped(tetromino) {
    if (tetromino.col < 0) {
      return true
    } else {
      return false
    }
  }

  rightOverlapped(tetromino) {
    if (tetromino.col + tetromino.width > this.boardWidth) {
      return true
    } else {
      return false
    }
  }

  bottomOverlapped(tetromino) {
    if (tetromino.row + tetromino.height > this.boardHeight) {
      return true
    } else {
      return false
    }
  }

  landedOverlapped(tetromino) {
    for (let i = 0; i < tetromino.height; i++) {
      for (let j = 0; j < tetromino.width; j++) {
        if (tetromino.shape[i][j] > 0 &&
          this.landedBoard[tetromino.row + i][tetromino.col + j] > 0) {
          return true
        }
      }
    }
    return false
  }

  mergeCurrentTetromino() {
    for (let i = 0; i < this.currentTetromino.height; i++) {
      for (let j = 0; j < this.currentTetromino.width; j++) {
        if (this.currentTetromino.shape[i][j] > 0) {
          this.landedBoard[this.currentTetromino.row + i][this.currentTetromino.col + j] = this.currentTetromino.shape[i][j]
        }
      }
    }
  }

  tryMoveDown() {
    if (this.gameOver) {
      return
    }
    
    this.progress()
    this.updateCurrentBoard()
    this.draw()
  }

  tryMoveLeft() {
    if (this.gameOver) {
      return
    }
    
    const tempTetromino = new this.currentTetromino.constructor(this.currentTetromino.row, this.currentTetromino.col - 1, this.currentTetromino.angle)
    if (!this.leftOverlapped(tempTetromino) &&
      !this.landedOverlapped(tempTetromino)) {
      this.currentTetromino.col -= 1
      this.updateCurrentBoard()
      this.draw()
    }
  }

  tryMoveRight() {
    if (this.gameOver) {
      return
    }
    
    const tempTetromino = new this.currentTetromino.constructor(this.currentTetromino.row, this.currentTetromino.col + 1, this.currentTetromino.angle)
    if (!this.rightOverlapped(tempTetromino) &&
      !this.landedOverlapped(tempTetromino)) {
      this.currentTetromino.col += 1
      this.updateCurrentBoard()
      this.draw()
    }
  }

  tryRotating() {
    if (this.gameOver) {
      return
    }
    
    const tempTetromino = new this.currentTetromino.constructor(this.currentTetromino.row + 1, this.currentTetromino.col, this.currentTetromino.angle)
    tempTetromino.rotate()
    if (!this.rightOverlapped(tempTetromino) &&
      !this.bottomOverlapped(tempTetromino) &&
      !this.landedOverlapped(tempTetromino)) {
      this.currentTetromino.rotate()
      this.updateCurrentBoard()
      this.draw()
    }
  }

  updateCurrentBoard() {
    for (let i = 0; i < this.boardHeight; i++) {
      for (let j = 0; j < this.boardWidth; j++) {
        this.currentBoard[i][j] = this.landedBoard[i][j]
      }
    }

    for (let i = 0; i < this.currentTetromino.height; i++) {
      for (let j = 0; j < this.currentTetromino.width; j++) {
        if (this.currentTetromino.shape[i][j] > 0) {
          this.currentBoard[this.currentTetromino.row + i][this.currentTetromino.col + j] = this.currentTetromino.shape[i][j]
        }
      }
    }
  }
  
  findClearableRows() {
    const clearableIndexes = []
    
    this.landedBoard.forEach((row, index) => {
      if (row.every(cell => cell > 0)) {
        clearableIndexes.push(index)
      }
    })
    
    return clearableIndexes
  }
  
  clearRows(rowIndexes) {
    for (let i = this.landedBoard.length - 1; i>=0; i--) {
      for (let j = 0; j < rowIndexes.length; j++) {
        if (rowIndexes[j] === i) {
          this.landedBoard.splice(rowIndexes[j], 1)
        }
      }
    }
    
    for (let i = 0; i < rowIndexes.length; i++) {
      this.landedBoard.unshift(new Array(this.boardWidth).fill(0))
    }
  }
  
  calculateScore(rowsCount) {
    return (rowsCount * (rowsCount + 1)) / 2
  }
  
  isGameOver() {
    for (let i = 0; i < this.boardWidth; i++) {
      if (this.landedBoard[2][i] > 0) {
        return true
      }
    }
    
    return false
  }
}

class Tetromino {
  constructor(row, col, angle = 0) {
    if (this.constructor === Tetromino) {
      throw new Error("This is an abstract class.")
    }
    this.row = row
    this.col = col
    this.angle = angle
  }

  get shape() {
    return this.constructor.shapes[this.angle]
  }

  get width() {
    return this.shape[0].length
  }

  get height() {
    return this.shape.length
  }

  fall() {
    this.row += 1
  }

  rotate() {
    if (this.angle < 3) {
      this.angle += 1
    } else {
      this.angle = 0
    }
  }

  move(direction) {
    if (direction === 'left') {
      this.col -= 1
    } else if (direction === 'right') {
      this.col += 1
    }
  }
}

class LShape extends Tetromino {}

LShape.shapes = [
  [
    [1, 0],
    [1, 0],
    [1, 1]
  ],

  [
    [1, 1, 1],
    [1, 0, 0]
  ],

  [
    [1, 1],
    [0, 1],
    [0, 1]
  ],

  [
    [0, 0, 1],
    [1, 1, 1]
  ]
]

LShape.color = 'rgb(255, 87, 34)'

class JShape extends Tetromino {}

JShape.shapes = [
  [
    [0, 2],
    [0, 2],
    [2, 2]
  ],

  [
    [2, 0, 0],
    [2, 2, 2]
  ],

  [
    [2, 2],
    [2, 0],
    [2, 0]
  ],

  [
    [2, 2, 2],
    [0, 0, 2]
  ]
]

JShape.color = 'rgb(63, 81, 181)'

class OShape extends Tetromino {}

OShape.shapes = [
  [
    [3, 3],
    [3, 3]
  ],

  [
    [3, 3],
    [3, 3]
  ],

  [
    [3, 3],
    [3, 3]
  ],

  [
    [3, 3],
    [3, 3]
  ]
]

OShape.color = 'rgb(255, 235, 59)'

class TShape extends Tetromino {}

TShape.shapes = [
  [
    [0, 4, 0],
    [4, 4, 4]
  ],

  [
    [4, 0],
    [4, 4],
    [4, 0]
  ],

  [
    [4, 4, 4],
    [0, 4, 0]
  ],

  [
    [0, 4],
    [4, 4],
    [0, 4]
  ]
]

TShape.color = 'rgb(156, 39, 176)'

class SShape extends Tetromino {}

SShape.shapes = [
  [
    [0, 5, 5],
    [5, 5, 0]
  ],

  [
    [5, 0],
    [5, 5],
    [0, 5]
  ],

  [
    [0, 5, 5],
    [5, 5, 0]
  ],

  [
    [5, 0],
    [5, 5],
    [0, 5]
  ]
]

SShape.color = 'rgb(76, 175, 80)'

class ZShape extends Tetromino {}

ZShape.shapes = [
  [
    [6, 6, 0],
    [0, 6, 6]
  ],

  [
    [0, 6],
    [6, 6],
    [6, 0]
  ],

  [
    [6, 6, 0],
    [0, 6, 6]
  ],

  [
    [0, 6],
    [6, 6],
    [6, 0]
  ]
]

ZShape.color = 'rgb(183, 28, 28)'

class IShape extends Tetromino {}

IShape.shapes = [
  [
    [7],
    [7],
    [7],
    [7]
  ],

  [
    [7, 7, 7, 7]
  ],

  [
    [7],
    [7],
    [7],
    [7]
  ],

  [
    [7, 7, 7, 7]
  ]
]

IShape.color = 'rgb(0, 188, 212)'

document.addEventListener('DOMContentLoaded', () => {
  const game = new Game()
  game.updateCurrentBoard()
  game.draw()
  game.play()

  window.addEventListener('keydown', (event) => {
    switch (event.keyCode) {
      case 37: // Left
        game.tryMoveLeft()
        break

      case 38: // Up
        game.tryRotating()
        break

      case 39: // Right
        game.tryMoveRight()
        break

      case 40: // Down
        game.tryMoveDown()
        break
    }
  })
})
!
999px

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