JSFiddle - React, Tailwind, and code Playground

JavaScript

var isDefined = function(value, path) {
  path.split('.').forEach(function(key) { value = value && value[key]; });
  return (typeof value != 'undefined' && value !== null);
};

var t = {a: {a1: 33, a12: {aa1d: 444, cc: 3}}, b: 00};

var results = '';
['a.a12.cc', 'a.a1.cc'].forEach(function(path) {
    results += 't[' + path + '] = ' + isDefined(t, path) + '\n';
});

document.body.appendChild(document.createElement('pre')).textContent = results;