optional chaining not working code example

Example 1: conditional chaining chrome

const nameLength = db?.user?.name?.length; // property
const adminOption = db?.user?.validateAdminAndGetPrefs?.().option; // functions
const optionLength = db?.user?.preferences?.[optionName].length; // dynamic property
const userName = usersArray?.[userIndex].name; // on arrays

Example 2: optional chaining in javascript

let myMap = new Map();
myMap.set("foo", {name: "baz", desc: "inga"});

let nameBar = myMap.get("bar")?.name;

Example 3: optional chaining

const array = [1,2,3,4,5];
let arrItem = array?.[4]; 

console.log(arrItem); /// 5