refactor: new node features

[NotSugden]

Please describe the changes this PR makes and why it should be merged:
This PR makes use of optional chaining and the nullish coalescing operator in various places, added in node v14,

aswell as a couple logic changes to use && instead of a tenary like x ? y : null where x can be null

Status

• Code changes have been tested against the Discord API, or there are no code changes
  • untested as of yet
  • i might need some help fully testing this just because changing || to ?? may cause some unintended behaviour
• I know how to update typings and have done so, or typings don't need updating

Semantic versioning classification:

• This PR changes the library's interface (methods or parameters added)
  • This PR includes breaking changes (methods removed or renamed, parameters moved or removed)
• This PR only includes non-code changes, like changes to documentation, README, etc.

[BannerBomb]

Sorry for posting all the links. It just made it easier and quicker to do that than to comment on each line.

Shouldn't this be if (cache) existing._patch?.(data);. The code is already checking that the variable "existing" isn't undefined and on this line before you made the change was if (existing._patch &&
https://github.com/discordjs/discord.js/pull/5132/files#diff-19338f04c86e704e9e4cb898fc9d21411ca4774ecae906a4e3179a306f55974dR25

Shouldn't this be if (cache) existing?._patch?.(data);. The code before you made the change was if (existing && existing._patch &&.
https://github.com/discordjs/discord.js/pull/5132/files#diff-649365ccd46d128b24504a4bcbb566995be7338be1ca43868ad43ae9eaf802e7R46
Should be

This is missing a .delete() at the end of the api.
https://github.com/discordjs/discord.js/pull/5132/files#diff-0362e882b074f7f48e846fdc34e56a307b11eb067d140ddd0ec4b095cf86ce74R60-R63

All of the below can be ignored if they were intentionally done that way. I just brought them up because the other changes I saw were being made.

This isn't a error, but just a suggestion. Couldn't you use a for loop instead of reduce on these since all that's being done here is setting data to a collection, and for loops are significantly faster at iterations?
It would also make them consistent with fetchInvites, fetchWebhooks, fetchVoiceRegions.
https://github.com/discordjs/discord.js/pull/5132/files#diff-9c03fb4d8c1b03db876641d3900a9c08f5a3a30be8d8a3b9840018507243c284R668-R674
https://github.com/discordjs/discord.js/pull/5132/files#diff-9c03fb4d8c1b03db876641d3900a9c08f5a3a30be8d8a3b9840018507243c284R708
https://github.com/discordjs/discord.js/pull/5132/files#diff-9c03fb4d8c1b03db876641d3900a9c08f5a3a30be8d8a3b9840018507243c284R695-R698

Did you mean to leave these as Promise.reject instead of changing them to throw?
https://github.com/discordjs/discord.js/pull/5132/files#diff-9c03fb4d8c1b03db876641d3900a9c08f5a3a30be8d8a3b9840018507243c284R1383
https://github.com/discordjs/discord.js/pull/5132/files#diff-6931a2b8bde677910786bd21afe3bc29740277d6510de785acfebca7e616ad89R257

Can't you just return the this._patch method here since that method already returns "this" itself?
https://github.com/discordjs/discord.js/pull/5132/files#diff-771d176d28e8d7cd4ba65413e0562da9908ee989169a6d1b1aac819ed472cc40R147-R148
https://github.com/discordjs/discord.js/pull/5132/files#diff-771d176d28e8d7cd4ba65413e0562da9908ee989169a6d1b1aac819ed472cc40R166-R167

[NotSugden]

Can't you just return the this._patch method here since that method already returns "this" itself?

actually, these methods should return void to be consistent with all of the other _patch methods

Did you mean to leave these as Promise.reject instead of changing them to throw?

fixed

This isn't a error, but just a suggestion. Couldn't you use a for loop instead of reduce on these since all that's being done here is setting data to a collection, and for loops are significantly faster at iterations?
It would also make them consistent with fetchInvites, fetchWebhooks, fetchVoiceRegions.
[...]

can you leave review comments on these lines? because the links you provided don't take me to them

Shouldn't this be if (cache) existing?._patch?.(data);. The code before you made the change was if (existing && existing._patch &&.

i think every structure has _patch anyway, but ill add that just to make sure

[iCrawl]

This looks mostly fine, only nit I would have is that you switched some for loops where you set into a collection to .reduce but left others intact. Should decide on one pattern over the other, but not mix-match so much.

[NotSugden]

ill switch for loops to reduce, map, etc where possible

[kyranet]

You can also replace all EventEmitter#removeListener with the newer EventEmitter#off, since we use EventEmitter#on over EventEmitter#addListener.

[kyranet]

You can also replace all EventEmitter#removeListener with the newer EventEmitter#off, since we use EventEmitter#on over EventEmitter#addListener.

[kyranet]

There are many cases where Array#reduce was used to fill an array of the same size, Array#map should be used instead.

I also found a lot of inconsistencies from existing code (not from this PR) regarding permissions:

In most cases, we assume permissionsFor(this.client.user) will always return a non-null value, which it indeed will, more than 99.99% of cases (when the GUILD intent is used (which discord.js needs to operate), Discord always sends the client's member, as such, guild.me is always available, even without the members or the presence intents).

The only case at which it can be null, is when a user sweeps discord.js's caches to save memory, (a practice that was discouraged, but was quite common regardless) but did not account for re-adding guild.me back, which lack breaks most of the library.

We need to consolidate this and decide what should we do in this regard, since in regular conditions this code will always work, it's the user's interference in discord.js's cache what makes it break.

Returning (not null, but undefined) in the getters is something I don't really agree with, and should be discussed.

[NotSugden]

In https://github.com/discordjs/discord.js/blob/stable/src/util/DataResolver.js#L42 you can use optional chaining

its already being used there

[advaith1]

https://github.com/discordjs/discord.js/pull/5132/files#diff-919bb374deac8ecaa94a5d6f70403ba5e0287487076c056028491697f58d4606R40

Stale

Strale

[iCrawl]

This needs a rebase.

[vladfrangu]

#5132 (comment) and #5132 (comment), not to mention that, and you won't believe it, this needs another rebase

[NotSugden]

reeeebased

Stale

[vladfrangu]

Small thing, otherwise LGTM

[SpaceEEC]

Three tiny nits left, otherwise LGTM.

wrong