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HTML

              
                <div id="root"></div>
              
            
!

CSS

              
                body {
  margin: 0;
  padding: 0;
  background-color: #E6E7E8;
}
              
            
!

JS

              
                const routeReducers = reducers => (state, action) =>
  reducers[action.type] ? reducers[action.type](state, action) : state;

const CellType = {
  EMPTY: "EMPTY",
  OLD: "OLD",
  NEW: "NEW"
};

const grid = (rows, cols, value) => {
  let cells = [];
  for (let i = 0, j; i < rows; i++) {
    cells[i] = [];
    for (j = 0; j < cols; j++) {
      cells[i][j] = value(i, j);
    }
  }
  return cells;
};

const setCellType = (cellType, cells, position) =>
  cells.map(
    (row, rowIndex) =>
      rowIndex === position.row
        ? row.map(
            (col, colIndex) =>
              colIndex === position.col ? { type: cellType } : col
          )
        : row
  );

const get = (row, col, cells) => {
  const rowLength = cells.length,
    colLength = cells[0].length;
  return cells[(row + rowLength) % rowLength][(col + colLength) % colLength];
};

const aliveNeighbours = (row, col, cells) =>
  [
    get(row - 1, col - 1, cells),
    get(row - 1, col, cells),
    get(row - 1, col + 1, cells),
    get(row, col - 1, cells),
    get(row, col + 1, cells),
    get(row + 1, col - 1, cells),
    get(row + 1, col, cells),
    get(row + 1, col + 1, cells)
  ].filter(cell => cell.type !== CellType.EMPTY).length;

const next = (row, col, cells) => {
  const cell = cells[row][col],
    neighbours = aliveNeighbours(row, col, cells);
  switch (cell.type) {
    case CellType.EMPTY:
      return neighbours === 3 ? { type: CellType.NEW } : cell;
    case CellType.NEW:
    case CellType.OLD:
      return neighbours === 2 || neighbours === 3
        ? { type: CellType.OLD }
        : { type: CellType.EMPTY };
    default:
      return cell;
  }
};

const store = Redux.createStore(
  routeReducers({
    initialize: (state, action) => {
      const cellTypes = [CellType.EMPTY, CellType.NEW, CellType.OLD];
      return {
        cells: grid(50, 50, () => ({
          type: cellTypes[Math.floor(Math.random() * 3)]
        })),
        generation: 0
      };
    },
    tick: (state, action) => ({
      ...state,
      cells: state.cells.map((row, rowIndex) =>
        row.map((col, colIndex) => next(rowIndex, colIndex, state.cells))
      ),
      generation: state.generation + 1
    }),
    toggle: (state, action) => {
      let cell = state.cells[action.position.row][action.position.col];
      switch (cell.type) {
        case CellType.EMPTY:
          return {
            ...state,
            cells: setCellType(CellType.NEW, state.cells, action.position)
          };
        case CellType.NEW:
        case CellType.OLD:
          return {
            ...state,
            cells: setCellType(CellType.EMPTY, state.cells, action.position)
          };
        default:
          return state;
      }
    },
    clear: (state, action) => ({
      cells: grid(50, 50, () => ({ type: CellType.EMPTY })),
      generation: 0
    }),
    setTimer: (state, action) => ({
      ...state,
      timer: action.timer
    })
  })
);

const run = () => {
  if (!store.getState().timer)
    store.dispatch({
      type: "setTimer",
      timer: setInterval(() => store.dispatch({ type: "tick" }), 100)
    });
};

const pause = () => {
  const timer = store.getState().timer;
  if (timer) store.dispatch({ type: "setTimer", timer: clearInterval(timer) });
};

const toggle = position => {
  store.dispatch({ type: "toggle", position });
};

const clear = () => {
  pause();
  store.dispatch({ type: "clear" });
};

const Header = () => {
  const headerStyle = {
    textAlign: "center",
    fontFamily: "Luckiest Guy",
    fontSize: "40px",
    color: "#01848F",
    marginTop: '10px'
  };
  return <div style={headerStyle}>Game Of Life</div>;
};

const Cell = ({ type, position }) => {
  const cellStyle = {
    width: "12px",
    height: "12px",
    border: "1px solid #9E9E9E",
    display: "inline-block",
    backgroundColor: type === CellType.NEW
      ? "#B2EBF2"
      : type === CellType.OLD ? "#006064" : "white"
  };
  return <div style={cellStyle} onClick={() => toggle(position)} />;
};

const CellRow = ({ row, rowIndex }) => {
  const rowStyle = {
    height: "12px",
    textAlign: "center"
  };
  return (
    <div style={rowStyle}>
      {row.map((cell, colIndex) =>
        <Cell
          type={cell.type}
          key={colIndex}
          position={{ row: rowIndex, col: colIndex }}
        />
      )}
    </div>
  );
};

const CellBoard = ({ cells }) => {
  return (
    <div>
      {cells.map((row, rowIndex) =>
        <CellRow row={row} key={rowIndex} rowIndex={rowIndex} />
      )}
    </div>
  );
};

const ActionButton = ({ buttonLabel, clickHandler }) => {
  const buttonStyle = {
    margin: "5px",
    padding: "5px",
    minWidth: "100px",
    backgroundColor: '#79C7C1',
    color: 'white',
    border: '1px solid transparent',
    fontSize: '18px',
    borderRadius: '5px',
    fontFamily: 'Open Sans',
    cursor: 'pointer'
  };
  return (
    <button style={buttonStyle} onClick={clickHandler}>{buttonLabel}</button>
  );
};

const Generation = ({ generation }) => {
  const generationStyle = {
    fontFamily: 'Open Sans',
    fontSize: '20px',
    color: '#01848F'
  };
  return <div style={generationStyle}>Generation: {generation}</div>;
};

const UserActions = ({
  runHandler,
  pauseHandler,
  clearHandler,
  generation
}) => {
  const actionStyle = {
    textAlign: "center",
    margin: "10px"
  };
  return (
    <div style={actionStyle}>
      <ActionButton buttonLabel="Run" clickHandler={run} />
      <ActionButton buttonLabel="Pause" clickHandler={pause} />
      <ActionButton buttonLabel="Clear" clickHandler={clear} />
      <Generation generation={generation} />
    </div>
  );
};

const App = ({ state }) => {
  return (
    <div>
      <Header />
      <UserActions generation={state.generation} />
      <CellBoard cells={state.cells} />
    </div>
  );
};

const render = () =>
  ReactDOM.render(
    <App state={store.getState()} />,
    document.getElementById("root")
  );

const isClear = (cells) => {
  for(let i = 0, j; i < cells.length; i++) {
    for(j = 0; j < cells[0].length; j++) {
      if(cells[i][j].type !== CellType.EMPTY) return false;
    }
  }
  return true;
}

store.subscribe(() => {
  const state = store.getState();
  if(state.timer && isClear(state.cells)) clear();
});
store.subscribe(render);

store.dispatch({type:'initialize'});
run();

              
            
!
999px

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