Write hardware in TypeScript. Test it with npm. Run it on an FPGA.

import { circuit, bit } from '@simten/core';
import { Xor, And, Or } from '@simten/core/std';
import { simulate } from '@simten/core/sim';

const HalfAdder = circuit('HalfAdder', {
  inputs:  { a: bit, b: bit },
  outputs: { sum: bit, carry: bit },
  nodes:   { xor1: Xor, and1: And },
  connect: ({ inputs, outputs, nodes: { xor1, and1 } }) => [
    inputs.a.to(xor1.a, and1.a),
    inputs.b.to(xor1.b, and1.b),
    xor1.out.to(outputs.sum),
    and1.out.to(outputs.carry),
  ],
});

const FullAdder = circuit('FullAdder', {
  inputs:  { a: bit, b: bit, cin: bit },
  outputs: { sum: bit, cout: bit },
  nodes:   { ha1: HalfAdder, ha2: HalfAdder, or1: Or },
  connect: ({ inputs, outputs, nodes: { ha1, ha2, or1 } }) => [
    inputs.a.to(ha1.a),
    inputs.b.to(ha1.b),
    ha1.sum.to(ha2.a),
    inputs.cin.to(ha2.b),
    ha2.sum.to(outputs.sum),
    ha1.carry.to(or1.a),
    ha2.carry.to(or1.b),
    or1.out.to(outputs.cout),
  ],
});

// Same engine in Node: no codegen, no testbench.
const sim = simulate(FullAdder);
sim.set({ a: 1, b: 1, cin: 1 });
console.log(sim.get('sum'), sim.get('cout')); // 1, 1

import { CircuitEmbed } from '@simten/embed';
import { HalfAdder } from './half-adder';

// Live, interactive hardware in three lines.
export default function Post() {
  return (
    <article>
      <p>Here's a half adder you can poke at:</p>
      <CircuitEmbed circuit={HalfAdder} />
    </article>
  );
}