#include "useState.cpp";
#include "Display.cpp";

long timer = 0;

Component component;

useState<int> counter {1};

void Header(int counter) {
  Serial.println("Counter: " + String(counter));
}

void setup() {
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
}

void loop() {
  // INCREMENT BY 1 EVERY 1s
  if (millis() - timer > 1000) {
    timer = millis();
    counter.set(counter.get() + 1);
  }
  // DISPLAY
  component.render(Header, counter);
}


sketch.ino

diagram.json

#ifndef USE_STATE
#define USE_STATE

template <class T>
class useState {
  public:
    useState(T initialState) {
      this->state = initialState;
    }

    void setUpdated(bool updated = false) {
      this->updated = updated;
    }

    void set(T newState) {
      this->state = newState;
      this->setUpdated(true);
    }

    T get() {
      this->setUpdated(false);
      return this->state;
    }

    bool isUpdated() {
      return this->updated;
    }
    
  private:
    T state;
    bool updated = true;
};

#endif //USE_STATE

useState.cpp

#include <Arduino.h>
#include "useState.cpp";

class Component {
  public:
    void render(void (*func)(int), useState<int> &counter) {
      if (counter.isUpdated()) {
        (*func)(counter.get());
      }
    }
};