JSFiddle - React, Tailwind, and code Playground

JavaScript

//this and objects
var person = {
    firstName: "Ryan",

    lastName: "Anklam",

    getFullName: function() {
        //inside an object we need to point to this to access its properties
        var firstName = "Yoko"; //this var is local to the function so, but 'this' still outputs Ryan
        return this.firstName + ' ' + this.lastName;
    },
    
    sayHello : function(){
        var that = this;  
        var inner = function(){
            //this inner function doesn't have privlaged access to the object's vars
            return that.getFullName() + " says hello";
        };
       
       return inner(); 
    }
};

console.log(person.getFullName());
console.log(person.sayHello ());