JavaScript: Optional chaining (?.)

 The optional chaining operator (?.) enables you to read the value of a property located deep within a chain of connected objects without having to check that each reference in the chain is valid.

The ?. operator is like the . chaining operator, except that instead of causing an error if a reference is nullish (null or undefined), the expression short-circuits with a return value of undefined. When used with function calls, it returns undefined if the given function does not exist.

The optional chaining operator provides a way to simplify accessing values through connected objects when it's possible that a reference or function may be undefined or null.
 

Example:

const customer = {
  name: "Carl",
  details: {
    age: 82,
    location: "Paradise Falls" // detailed address is unknown
  }
};

const customerCity = customer.details?.address?.city;

// … this also works with optional chaining function call

const customerName = customer.name?.getName?.();

// method does not exist, customerName is undefined

Readmore: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Optional_chaining