Is there something like optional chaining for assignment in JavaScript

Question

Optional chaining is a powerful feature when it comes to access data like

const options = cache.[server]?.[channel]?.[service]

Now when writing data we generally need to do something like

cache[server] ??=  {}
cache[server][channel] ??= {}
cache[server][channel][service] = options

Is there something like optional chaining that make assignment like this lighter (maybe in one line)?

Something like :

cache[server]??{}:[channel]??{}:[service]=options

In this case adding {} or [] just after would permit to indicate what's expected to assign if nullish.

As proposed by @Bergi, the nearest way of doing this is to write like that:

((cache[server] ??= {})[channel] ??= {})[service] = options

cache[server]??{}:[channel]??{}:[service]=options - and this is what I call a readable, clean code — kind user
– kind user, Commented Sep 25, 2020 at 11:56
@kinduser The syntax could be improved, but it would still be better than a series of if statements that create all the intermediate objects. — Barmar
– Barmar, Commented Sep 25, 2020 at 11:58

Bergi · Accepted Answer · 2020-09-25 13:10:53Z

2

You can use parenthesis to transform the

cache[server] ??= {}
cache[server][channel] ??= {}
cache[server][channel][service] = options

into a single expression

((cache[server] ??= {})[channel] ??= {})[service] = options

answered Sep 25, 2020 at 13:10

Bergi

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1 Comment

While it's not syntaxic sugar, it's the most modular way of doing what I asked