What is this "?." feature called, in JavaScript?

Question

Just realized it exists, thanks to VSCode enforcing it...

Usage

let regex = /hot/g;
let phrase = "It's hot, outside.";

// you don't need to worry about null
let matches = phrase.match(regex)?.length;

It's the "optional chaining operator", as per caniuse.com/#search=%3F. — Mike 'Pomax' Kamermans
– Mike 'Pomax' Kamermans, Commented Aug 29, 2020 at 1:48
As people answered it's called optional chaining, however it's also called elvis operator sometimes. — Yair Cohen
– Yair Cohen, Commented Aug 29, 2020 at 1:51
"The name "Elvis operator" refers to the fact that when its common notation, ?:, is viewed sideways, it resembles an emoticon of Elvis Presley with his quiff." - Wikipedia — Yair Cohen
– Yair Cohen, Commented Aug 29, 2020 at 1:52

Mosia Thabo · Accepted Answer · 2020-08-29 01:55:57Z

9

That feature is called optional chaining. This calls the method when the receiver is neither undefined nor null.

Mosia Thabo

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answered Aug 29, 2020 at 1:48

3limin4t0r

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