JSFiddle - React, Tailwind, and code Playground

JavaScript

var LibraryName = function () {
    //constructor stuff
}

LibraryName.prototype = {
    someValue: 0,
    firstFunc: function (stuff) {
        this.someValue = 99;
        this.secondFunction();
    },
    secondFunction: function () {
        this.doSomething(this.someValue);
    },
    doSomething: function(){
        console.log("success");
    }
}

var l = new LibraryName();
l.firstFunc();