example of debouncing for esp8266/esp32 using arduino framework

debounce.cpp

//This is how i typically handle button presses, while using a minimal amount of clock cycles / avoiding polling and still keeping it responsive:(note: interrupt callbacks should ideally be as simple as possible, so its better to have the logic outside of it.)
#include <Arduino.h>
#define GPIO_BUTTON 4
#define GPIO_LED 5

const uint16_t debounceDelay = 100;
unsigned long lastButtonPress = 0;
bool buttonPressed = false;

void IRAM_ATTR buttonInterrupt() {
    buttonPressed = true;
}
void buttonHandler() {
    if (buttonPressed) {
        buttonPressed = false;
        if (millis() - lastButtonPress > debounceDelay) {
            lastButtonPress = millis();
            //your button logic here
            digitalWrite(GPIO_LED, !digitalRead(GPIO_LED));
        }
    }
}
void setup() {
    pinMode(GPIO_BUTTON, INPUT_PULLUP);
    pinMode(GPIO_LED, OUTPUT);
    digitalWrite(GPIO_LED, LOW);
    attachInterrupt(GPIO_BUTTON, buttonInterrupt, FALLING);
}
void loop() {
    buttonHandler();
}