JSFiddle - React, Tailwind, and code Playground

JavaScript

function start(){
    var alert = new Alert(3);
    alert.startTimer();
    
    }
    function Alert(timer) {
        this.timerMinutes = timer;
        this.timerPos = 0;
    }
    
    Alert.prototype.startTimer = function() {
            this.timerPos = this.timerMinutes+1;
            this.timerInc();
        };
    
    
    Alert.prototype.timerInc = function() { 
        if (this.timerPos > 0){     
            this.timerPos--;
            console.log(this.timerPos);
            setTimeout(function(_this){_this.timerInc()},1000,this);
        }   
    };

start();