JSFiddle - React, Tailwind, and code Playground

HTML

<div id="out"></div>

JavaScript

function l(s) {
    $('#out').append($('<div />', {
        html: s.toString()
    }));
}

function BlahObj() {
    this.users = {};
}
BlahObj.prototype = {
    userGet: function(id) {
        if (this.users[id] !== undefined) {
            l(this.users[id]);
        }
    },
    userAdd: function(id, name) {
        if (this.users[id] === undefined) {
            this.users[id] = name;
        }
    },
    user: {
        get: function(id) {
            if (this.users[id] !== undefined) {
                l(this.users[id]);
            }
        }
    }
}

var test = new BlahObj();
test.userAdd(1, 'User A');
test.userAdd(2, 'User B');
test.userAdd(3, 'User C');
test.userGet(2);
try {
    test.user.get(1);
} catch (e) {
    l(e);
}