having-the-state1.js

let count = 0;
const doOnlyOnce = function (){
    if(count==0){
        console.log("You do this for first time.");
    }else{
        console.log("You already have done this.");
    }
    count++;
};

doOnlyOnce();  // "You do this for first time."
doOnlyOnce();  // "You already have done this."
doOnlyOnce();  // "You already have done this."