text: import { Universe, Cell } from "wasm-game-of-life";
  // Import the WebAssembly memory at the top of the file.
  import { memory } from "wasm-game-of-life/wasm_game_of_life_bg";
  
  const CELL_SIZE = 2; // px
  const GRID_COLOR = "#EEEEEE";
  const DEAD_COLOR = "#FFFFFF";
  const ALIVE_COLOR = "#e34572";
  
  // Construct the universe, and get its width and height.
  const universe = Universe.new();
  const width = universe.width();
  const height = universe.height();
  
  let animationId = null;
  
  // Give the canvas room for all of our cells and a 1px border
  // around each of them.
  const canvas = document.getElementById("game-of-life-canvas");
  canvas.height = (CELL_SIZE + 1) * height + 1;
  canvas.width = (CELL_SIZE + 1) * width + 1;
  
  const ctx = canvas.getContext("2d");
  
  const isPaused = () => {
    return animationId === null;
  };
  
  const playPauseButton = document.getElementById("play-pause");
  
  const play = () => {
    playPauseButton.textContent = "⏸";
    renderLoop();
  };
  
  const pause = () => {
    playPauseButton.textContent = "▶";
    cancelAnimationFrame(animationId);
    animationId = null;
  };
  
  playPauseButton.addEventListener("click", event => {
    if (isPaused()) {
      play();
    } else {
      pause();
    }
  });
  
  const renderLoop = () => {
    // debugger;
    universe.tick();
  
    drawGrid();
    drawCells();
  
    animationId = requestAnimationFrame(renderLoop);
  };
  
  const drawGrid = () => {
    ctx.beginPath();
    ctx.strokeStyle = GRID_COLOR;
  
    // Vertical lines.
    for (let i = 0; i <= width; i++) {
      ctx.moveTo(i * (CELL_SIZE + 1) + 1, 0);
      ctx.lineTo(i * (CELL_SIZE + 1) + 1, (CELL_SIZE + 1) * height + 1);
    }
  
    // Horizontal lines.
    for (let j = 0; j <= height; j++) {
      ctx.moveTo(0, j * (CELL_SIZE + 1) + 1);
      ctx.lineTo((CELL_SIZE + 1) * width + 1, j * (CELL_SIZE + 1) + 1);
    }
  
    ctx.stroke();
  };
  
  const getIndex = (row, column) => {
    return row * width + column;
  };
  
  const drawCells = () => {
    const cellsPtr = universe.cells();
    const cells = new Uint8Array(memory.buffer, cellsPtr, width * height);
  
    ctx.beginPath();
  
    // for (let row = 0; row < height; row++) {
    //   for (let col = 0; col < width; col++) {
    //     const idx = getIndex(row, col);
  
    //     ctx.fillStyle = cells[idx] === Cell.Dead ? DEAD_COLOR : ALIVE_COLOR;
  
    //     ctx.fillRect(
    //       col * (CELL_SIZE + 1) + 1,
    //       row * (CELL_SIZE + 1) + 1,
    //       CELL_SIZE,
    //       CELL_SIZE
    //     );
    //   }
    // }
  
    // Alive cells.
  ctx.fillStyle = ALIVE_COLOR;
  for (let row = 0; row < height; row++) {
    for (let col = 0; col < width; col++) {
      const idx = getIndex(row, col);
      if (cells[idx] !== Cell.Alive) {
        continue;
      }
  
      ctx.fillRect(
        col * (CELL_SIZE + 1) + 1,
        row * (CELL_SIZE + 1) + 1,
        CELL_SIZE,
        CELL_SIZE
      );
    }
  }
  
  // Dead cells.
  ctx.fillStyle = DEAD_COLOR;
  for (let row = 0; row < height; row++) {
    for (let col = 0; col < width; col++) {
      const idx = getIndex(row, col);
      if (cells[idx] !== Cell.Dead) {
        continue;
      }
  
      ctx.fillRect(
        col * (CELL_SIZE + 1) + 1,
        row * (CELL_SIZE + 1) + 1,
        CELL_SIZE,
        CELL_SIZE
      );
    }
  }
  
    ctx.stroke();
  };
  
  drawGrid();
  drawCells();
  // This used to be `requestAnimationFrame(renderLoop)`.
  play();
  
  canvas.addEventListener("click", event => {
    const boundingRect = canvas.getBoundingClientRect();
  
    const scaleX = canvas.width / boundingRect.width;
    const scaleY = canvas.height / boundingRect.height;
  
    const canvasLeft = (event.clientX - boundingRect.left) * scaleX;
    const canvasTop = (event.clientY - boundingRect.top) * scaleY;
  
    const row = Math.min(Math.floor(canvasTop / (CELL_SIZE + 1)), height - 1);
    const col = Math.min(Math.floor(canvasLeft / (CELL_SIZE + 1)), width - 1);
  
    universe.toggle_cell(row, col);
  
    drawGrid();
    drawCells();
  });
  