nes.js

import Bus from './nes/bus.js';
import RP2C02 from './nes/2c02.js';
import RP2A03 from './nes/2a03.js';
import MCS6502 from './6502.js';

export default (rom, {Hz}) => {
  const ram = [/* TODO */];
  const bus = Bus(rom, ram);
  const [
    processor,
    graphics,
    sound
  ] = [
    MCS6502(bus),
     RP2C02(bus),
     RP2A03(bus),
  ];

  return {
    data: {
      cpu: processor.data,
      ppu: graphics.data,
      apu: sound.data
    },

    emulate: (state, ms) => {
      const length = 1 + ms*Hz/1000;
      const frames = Array.from({length});
      const {
        cpu: [cpu],
        ppu: [ppu, frame],
        apu: [apu]
      } = frames.reduce(a => ({
        cpu: processor.emulate(a.cpu, 0),
        ppu: graphics.emulate(a.ppu),
        apu: sound.emulate(a.apu)
      }), state);

      return {
        frame,
        //cc,
        state: {
          cpu,
          ppu,
          apu
        },
        ms: frames.reduce(T => T - 1000/Hz, ms)
      };
    }
  };
};