JSFiddle - React, Tailwind, and code Playground

JavaScript

function isDefined(obj, keysString) {
    
        var keys = keysString.split('.');
        var tmp = obj;
    
        for(var i = 0; i < keys.length; i++) {
            tmp = tmp[keys[i]];
            
            if(typeof tmp === 'undefined') {
                return false;
            }
      
        }
        
        return true;
    }

console.log(isDefined({test: {nested: true}}, 'test.nested'));//true
console.log(isDefined({test: {nested: true}}, 'test.nested.supernested'));//false
console.log(isDefined({test: {nested: true}}, 'test.othernested.super'));//false