trivial heart beat state-machine simulation in js

heartbeat.js

class Heart {
  constructor() {
    this.states = {
      REST: 'Resting',
      CONTRACTION: 'Contracting',
      RELAXATION: 'Relaxing'
    };
    
    this.transitions = {
      [this.states.REST]: [this.states.CONTRACTION, 'Ventricles contract', 'Valves open'],
      [this.states.CONTRACTION]: [this.states.RELAXATION],
      [this.states.RELAXATION]: [this.states.REST, 'Ventricles relax', 'Valves close']
    };

    this.currentState = this.states.REST;
    this.internalState = 0;
  }

  simulateHeartbeat() {
    console.log(`Heart is ${this.currentState}`);
    
    const actions = this.transitions[this.currentState];
    for (const action of actions) {
      if (typeof action === 'string') {
        console.log(action);
      } else if (action === 'Ventricles contract') {
        this.internalState |= 1; // set first bit
      } else if (action === 'Ventricles relax') {
        this.internalState &= ~1; // clear first bit
      } else if (action === 'Valves open') {
        this.internalState |= 2; // set second bit
      } else if (action === 'Valves close') {
        this.internalState &= ~2; // clear second bit
      }
    }
    
    this.currentState = actions[0];
  }
}

const heart = new Heart();

// simulate heart pumping for a few cycles
for (let i = 0; i < 10; i++) {
  heart.simulateHeartbeat();
}