conway-react/src/lib.ts

export const generateNewGrid = (grid: boolean[][]) => {
  return [...grid].map((row, y) => {
    const newRow = [...row].map((cell, x) => {
      const isAlive = cell;
      const livingNeighbors = countLivingNeighbors(grid, x, y);

      if (isAlive) {
        if (livingNeighbors === 2 || livingNeighbors === 3) {
          return true;
        } else {
          return false;
        }
      } else {
        if (livingNeighbors === 3) {
          return true;
        }
      }

      return isAlive;
    });

    return newRow;
  });
};

export const countLivingNeighbors = (
  grid: boolean[][],
  x: number,
  y: number,
): number => {
  return getNeighbors(grid, x, y).filter((el) => el).length;
};

export const getNeighbors = (
  grid: boolean[][],
  x: number,
  y: number,
): boolean[] => {
  const neighbors = [];
  const height = grid.length;
  const width = grid[0].length;

  const isNotOnTopRow = y > 0;
  const isNotOnFarLeftRow = x > 0;
  const isNotOnBottomRow = y < height - 1;
  const isNotOnFarRightRow = x < width - 1;

  if (isNotOnTopRow) {
    neighbors.push(grid[y - 1][x]); // N
    if (isNotOnFarLeftRow) neighbors.push(grid[y - 1][x - 1]); // NW
    if (isNotOnFarRightRow) neighbors.push(grid[y - 1][x + 1]); // NE
  }

  if (isNotOnFarLeftRow) neighbors.push(grid[y][x - 1]); // W
  if (isNotOnFarRightRow) neighbors.push(grid[y][x + 1]); // E

  if (isNotOnBottomRow) {
    neighbors.push(grid[y + 1][x]); // S
    if (isNotOnTopRow) neighbors.push(grid[y + 1][x - 1]); // SW
    if (isNotOnFarRightRow) neighbors.push(grid[y + 1][x + 1]); // SE
  }

  return neighbors;
};

export const updateGridDimensions = (
  oldDimensions: {
    width: number;
    height: number;
  },
  newDimensions: { width?: number; height?: number },
  grid: boolean[][],
): boolean[][] => {
  const width = newDimensions.width ?? oldDimensions.width;
  const height = newDimensions.height ?? oldDimensions.height;

  grid = [...grid];

  if (height > oldDimensions.height) {
    while (grid.length < height) {
      grid.push(Array(width).fill(false));
    }
  } else if (height < oldDimensions.height) {
    while (grid.length > height) {
      if (grid.length <= 1) break;
      grid.pop();
    }
  }

  if (width > oldDimensions.width) {
    grid = grid.map((row) => {
      while (row.length < width) {
        row.push(false);
      }

      return row;
    });
  } else if (width < oldDimensions.width) {
    grid = grid.map((row) => {
      while (row.length > width) {
        if (row.length <= 1) break;
        row.pop();
      }

      return row;
    });
  }

  return grid;
};