Conway.js

// work in progress

// white
const dead = 0;
// black
const alive = 1;

const asIs = 2;

// Get all alive neighbours
const aliveNeighbours = (neighbours) => neighbours.filter(neighbour => neighbour === alive);

// A living cell with less than 2 live neighbors dies
const rule1 = (neighbours) => neighbours[4] === alive && aliveNeighbours(neighbours).length - 1 < 2 ? dead : asIs;

// A living cell with 2 or 3 live neighbors lives
const rule2 = (neighbours) => {
  if(neighbours[4] === alive){
  const count = aliveNeighbours(neighbours).length - 1;
  return count === 2 || count === 3 ? alive : dead;
  }
  return asIs;
};

describe('In Conways Game of Life', function() {
  it('A living cell with less than 2 live neighbors dies', function() {
    const neighbours = [dead, dead, dead, dead, alive, dead, dead, dead, alive];
    assert.equal(rule1(neighbours), dead);
  });


  it('A living cell with 2 or 3 live neighbors lives', function() {
    let neighbours = [dead, dead, dead, alive, dead, dead, alive, alive];
    assert.equal(rule2(neighbours), dead);
    neighbours = [dead, alive, dead, alive, dead, alive, alive, alive];
//    assert.equal(rule2(neighbours), alive);
  });
});