JavaScript Optional Chaining

The optional chaining operator is a new feature coming in the next ECMAScript standard.

It’s still not official, but available in Chrome 80 behind a flag.

Have you ever used the && operator as a fallback? It’s one of my favorite JavaScript features.

In JavaScript, you can first check if an object exists, and then try to get one of its properties, like this:

const car = null
const color = car && car.color

Even if car is null, you don’t have errors and color is assigned the null value.

You can go down multiple levels:

const car = {}
const colorName = car && car.color && car.color.name

In some other languages, using && might give you true or false, since it’s usually a logic operator.

Not in JavaScript, and it allows us to do some cool things.

Now this new optional chaining operator will let us be even more fancy:

const color = car?.color
const colorName = car?.color?.name

If car is null or undefined, the result will be undefined.

With no errors (while with && in case car was undefined we had a ReferenceError: car is not defined error)

You can use this syntax today using this Babel plugin.