JSFiddle - React, Tailwind, and code Playground

JavaScript

function MyObject() {
    var self = this;
    
    var innerMethod = function() {
        alert("inner method, self == this?: " + self == this); // false
        alert("inner method: " + this); // [object Window]
        alert("closest constructor name of in prototype chain ?: "+ this.__proto__.constructor.name); // Window
    }
    
    this.outerMethod = function(){
        innerMethod(); 
        alert("outer method: " + this); // [object MyObject]
        alert("closest constructor name in prototype chain?: "+ this.__proto__.constructor.name); // MyObject
    }
}

var o = new MyObject();
o.outerMethod();