pseudo schooner
Hey so i would like a function similar to this:
function filterCh(channels:GuildBasedChannel[], [ChannelType.PrivateThread,ChannelType.PublicThread]:ChannelTypes[])
that should return PrivateThreadChannel| PublicThreadChannel
But it doesnt seem to work at all, i also tried with single types and its only working for single objs
main marsh
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pseudo schooner
djs 14.7.1
node v18.3.0
smoky citrus
i really need test environment
pseudo schooner
should i create a sandbox ?
smoky citrus
use what
pseudo schooner
i tried... but its doesnt really solve any problem
at least from what i thought...
hollow hinge
filter narrows the type if you provide it with a typeguarding function, a simple comparison only returns a boolean as you can see
pseudo schooner
so how would you get the correct typeguard from the ChannelType enum ?
hollow hinge
you have to annotate your arrow funtion: (c): c is ... => c.type === ...
pseudo schooner
i do understand but it wouldnt work for a dynamic channeltype and is the same as casting it pretty muhc
that actually should give an error, but it doesnt 🤔 same as type casting,
thick fossil
You tell it a lie in your type annotations. That’s why it doesn’t error
pseudo schooner
yeah i know, so it really isnt a solution to my problem 🔝
thick fossil
It sure is, if you stopped lying to TS. Use a generic and pass that generic in the typeguard
pseudo schooner
mhm i dont understand how to use a generic here, you have an example
passing the channeltype as generic ? ChannelType is an enum tho...
hollow hinge
you provide the type to the function in your example, so use a generic parameter for this type
you can use the generic in the typeguard e.g. with Extract since Channel is a union type
pseudo schooner
i dont provide a type, i provide the ChannelType enum
hollow hinge
you have a parameter you assign one of the enum values to
pseudo schooner
i cant understand, i m sorry. Can you use the variable name ?
I use an array of enums through which the channel array should return the according type
It does if you do it for a single object, in my example you can call single.ownerId
if you do the same with the array it still returns GuildBasedChannel instead of PublicThreadChannel
--
Furthermore i want to provide an array of enums so the enums are dynamic => i cant cast them...
hollow hinge
you can Extract different types of channels from Channel with a generic parameter, you can use generics for array parameters
pseudo schooner
can you write me an example?
...
i am probably far off from what you want to explain me, sorry!
hollow hinge
smoky citrus
imo best way even if overwriting
hollow hinge
there's a reason ts doesn't allow you to cast the return type of filter to T[]
smoky citrus
well yes but
hollow hinge
the function returns an array of channels, not channel types
indigo warren
