What is optional chaining?

According to MDN official docs, the optional chaining operator (?.) permits reading the value of a property located deep within a chain of connected objects without having to expressly validate 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.

 const adventurer = {
   name: "Alice",
   cat: {
     name: "Dinah",
   },
 };

 const dogName = adventurer.dog?.name;
 console.log(dogName);
 // expected output: undefined

 console.log(adventurer.someNonExistentMethod?.());
 // expected output: undefined