structuring shits up

src/js/automata.js

@@ -0,0 +1,52 @@
+// TODO: Hide accumulator inside
+function evolve(state, acc, rules) {
+  const [x, y, z, ...xs] = state;
+  if (!xs.length) {
+    return acc[acc.length - 1] + acc + acc[0];
+  }
+
+  const rule = x + y + z;
+  const newAcc = acc.concat(rules[rule]);
+  return evolve(y + z + xs.join(''), newAcc, rules);
+}
+
+function conwayRules(cell, neighbors) {
+  // loneliness rule
+  if (cell === 1 && neighbors < 2) return 0;
+  // overpopulation rule
+  if (cell === 1 && neighbors > 3) return 0;
+  // born when three live neighbors rule
+  if (cell === 0 && neighbors === 3) return 1;
+  // the cell remains the same if none apply
+  return cell;
+}
+
+function getDrawingValues(state, acc, cell) {
+  const d = cell.dimension;
+  return Object.keys(state).map(
+    (key) => {
+      const fillStyle = state[key] === '1' ? cell.liveColor : cell.deadColor;
+      return {
+        move: [key * d, acc * d],
+        fill: [key * d, acc * d, d, d],
+        fillStyle,
+      };
+    },
+  );
+}
+
+function initialState1D(width, initFn, args) {
+  return [...Array(width)].map(
+    () => initFn(...args).toString(),
+  ).join('');
+}
+
+function initialState2D(width, height, initFn, args) {
+  return [...Array(height)].map(
+    () => [...Array(width)].map(() => initFn(...args)),
+  );
+}
+
+export {
+  evolve, getDrawingValues, initialState1D, initialState2D,
+};