Transducer based, branch-less 1D Wolfram automata (textmode)

wolfram.js

const tx = require("@thi.ng/transducers");
const txb = require("@thi.ng/transducers-binary");

// ANSI clear screen esc seq
const CLEAR = "\x1b[2J\x1b[;H";

// CA dimensions
const WIDTH = 72;
const HEIGHT = 24;

// Wolfram rule ID
const RULE = 22;

// seed w/ 25% probability
const seed = () => [...txb.randomBits(0.25, WIDTH)];

// separate rule ID into bits
const parseRule = (id) => [...txb.bits(8, false, [id])];

// single evolution step
const evolve = (kernel, rule) => (src) =>
    tx.transduce(
        tx.comp(
            // convolve curr generation w/ kernel
            tx.convolve1d({
                src,
                kernel,
                width: src.length,
                wrap: true
            }),
            // apply rule
            tx.map(tx.lookup1d(rule))
        ),
        tx.push(),
        tx.range(src.length)
    );

// CA update as dynamically built transducer, wrapped in
// `tx.step()` for stepwise execution via setInterval (below)
const update = tx.step(
    tx.comp(
        // evolve current generation
        tx.scan(
            tx.reducer(
                seed,
                evolve(
                    tx.buildKernel1d([1, 2, 4], 3),
                    parseRule(RULE)
                )
            )
        ),
        // transform new gen into ASCII art
        tx.map((gen) => gen.map((x) => (x ? "#" : " ")).join("")),
        // form sliding window of max `HEIGHT` last results
        tx.slidingWindow(HEIGHT),
        // join all lines into single string, prefix w/ clear screen cmd
        tx.map((win) => CLEAR + win.join("\n")),
        // print
        tx.trace()
    )
);

// kick off
setInterval(update, 16);