const int buttonPin = D1;
const int ledPin = D0;
int buttonState = 0;
void setup() {
  // put your setup code here, to run once:
  pinMode(ledPin,OUTPUT);
  pinMode(buttonPin, INPUT_PULLDOWN);
  digitalWrite(ledPin,HIGH);

}

void loop() {
  // put your main code here, to run repeatedly:
  buttonState = digitalRead(buttonPin);
  if (buttonState == HIGH){
    digitalWrite(ledPin,HIGH);

  }else{

    digitalWrite(ledPin, LOW);
  }

}