JSFiddle - React, Tailwind, and code Playground

JavaScript

var API = (function() {

    function API() {};

    API.prototype.get = function() {
        // can call private_method.
        private_method();
    }

    // Accessible from the object created in this scope.
    function private_method() {
        console.log('in private method');
    }

    return API;

})();

// API is now reusable as a global variable.
var api = new API();

api.get();