Optional_Chaining

？

Now if you want to know whether a restaurant’s opening hours in Monday

1

console.log(restaurant.openingHours.mon);

If mon is not exist, it will be undefined, not a big deal.

But if openingHours is not exist ,it will be a error.

So we can solve this problem with the ?

1

console.log(restaurant.openingHours?.mon);

We can also use it to use method.

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console.log(restaurant.order?.(0,1) ?? 'Method does not exist.')