JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://getfirebug.com/firebug-lite-debug.js"></script>
<div>
    <h2>deep merge objects</h2>
</div>

JavaScript

var o = {
  customerInfo: {
    fname: "Tom",
    lname: "Smith",
    age: 23,
    height: 160,
    paymentMethods: {
      paypal: {
        username: "sally"
      }
    }
  },
  car: {
    color: "red",
    numWheels: 4
  }
};

// this wipes out more deeply nested things (paypal disappears)
var merge = $.extend(true, {} , o.customerInfo, {
    "fname": "Sally",
    lname: "Adams",
    mname: "Tully",
    paymentMethods: {
      visa: {
        lastFour: "5555"
      }
    }
});

console.dir(merge);