Initial data commit

Task/Elementary-cellular-automaton/JavaScript/elementary-cellular-automaton.js

@@ -0,0 +1,46 @@
+const alive = '#';
+const dead = '.';
+
+// ------------------------------------------------------------[ Bit banging ]--
+const setBitAt = (val, idx) => BigInt(val) | (1n << BigInt(idx));
+const clearBitAt = (val, idx) => BigInt(val) & ~(1n << BigInt(idx));
+const getBitAt = val => idx => (BigInt(val) >> BigInt(idx)) & 1n;
+const hasBitAt = val => idx => ((BigInt(val) >> BigInt(idx)) & 1n) === 1n;
+
+// ----------------------------------------------------------------[ Utility ]--
+const makeArr = n => Array(n).fill(0);
+const reverse = x => Array.from(x).reduce((p, c) => [c, ...p], []);
+const numToLine = width => int => {
+  const test = hasBitAt(int);
+  const looper = makeArr(width);
+  return reverse(looper.map((_, i) => test(i) ? alive : dead)).join('');
+}
+
+// -------------------------------------------------------------------[ Main ]--
+const displayCA = (rule, width, lines, startIndex) => {
+  const result = [];
+  result.push(`Rule:${rule} Width:${width} Gen:${lines}\n`)
+  const ruleTest = hasBitAt(rule);
+  const lineLoop = makeArr(lines);
+  const looper = makeArr(width);
+  const pLine = numToLine(width);
+
+  let nTarget = setBitAt(0n, startIndex);
+  result.push(pLine(nTarget));
+  lineLoop.forEach(() => {
+    const bitTest = getBitAt(nTarget);
+    looper.forEach((e, i) => {
+      const l = bitTest(i === 0 ? width - 1 : i - 1);
+      const m = bitTest(i);
+      const r = bitTest(i === width - 1 ? 0 : i + 1);
+      nTarget = ruleTest(
+          parseInt([l, m, r].join(''), 2))
+          ? setBitAt(nTarget, i)
+          : clearBitAt(nTarget, i);
+    });
+    result.push(pLine(nTarget));
+  });
+  return result.join('\n');
+}
+
+displayCA(90, 57, 31, 28);