ESP32 LED Blink without ［delay］

#define OnB_LED 2

int LedState = 0;
unsigned long previousMillis = 0;

void setup() {
  pinMode(OnB_LED, OUTPUT);
}

void loop()
{
  unsigned long currentMillis = millis();

  if(currentMillis - previousMillis >= 1000) {
    if (LedState == 0) {
       digitalWrite(OnB_LED, HIGH);
       LedState = 1;
    }
    else {
       digitalWrite(OnB_LED, LOW);
       LedState = 0;
    }
    previousMillis = currentMillis;
  }

}