int led=D12;
int but=D1;

void setup() {
  // put your setup code here, to run once:
pinMode(but,INPUT);
pinMode(led, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
 if (digitalRead(but)==HIGH){
    
    digitalWrite(led, HIGH);
   
  // while(digitalRead(but));
  }
  else{
        digitalWrite(led, LOW);
  }
}