// constants won't change
#define button 4 // ESP32connected to button's pin
#define LED 2 // ESP32 pin connected to LED's pin
// variables will change:
int ledState = LOW;     // the current state of LED
int lastButtonState;    // the previous state of button
int currentButtonState; // the current state of button
void setup() 
{
  pinMode(button, INPUT_PULLUP); // set ESP32 pin to input pull-up mode
  pinMode(LED, OUTPUT);          // set ESP32 pin to output mode
  currentButtonState = digitalRead(button);
}
void loop() {
  lastButtonState    = currentButtonState;      // save the last state
  currentButtonState = digitalRead(button); // read new state
  if(lastButtonState == HIGH && currentButtonState == LOW) 
  {
    ledState = !ledState;
    // control LED arccoding to the toggled state
    digitalWrite(LED, ledState); 
  }
  delay(100);
}