JSFiddle - React, Tailwind, and code Playground

JavaScript

var Bot = function () {
    this.updateInterval = 5000;
    this.updateTimer = null;
};

Bot.prototype.getUpdates = function () {
    var self = this;
    alert("b " + self.updateInterval); // returns "b undefined"
};

Bot.prototype.init = function () {
    var self = this;
    $.get('/', function (data, status) {
        alert("a " + self.updateInterval); // returns "a 5000"
        self.updateTimer = setInterval(self.getUpdates.bind(self), self.updateInterval);
    });
};
window.bot = new Bot();
window.bot.init();