chain expression javascript code example

Example 1: optional chain operator

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

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

Example 2: optional chaining

/* 
* optional chaining (?.) allows me to write code that stops 
* running when we encounter a null or undefined value
*/

function tryGetFirstElement<T>(arr?: T[]) {
    return arr?.[0];
    // equivalent to
    //   return (arr === null || arr === undefined) ?
    //       undefined :
    //       arr[0];
}