Since TypeScript 3.4, it refuses to do recursive operation. Must fix it somehow.

The Drop type has an infinite instantiation when used in a generic

Drop<any[], number>; // This throws an "infinite instantiation" error
Drop<[], number>;    // The first parameter is specific, the second generic, this is OK
Drop<any[], 0>;      // The first parameter is generic, the second specific, this is also OK

Is there a specific reason why the package doesn't provide implementations for basic operations? Are there any plans for adding them in the future? I ended up writing some implementations for these types since I needed to work with tuples. Perhaps the types could be contributed to fp-ts Tuple module if they had an implementation? See gcanti/fp-ts#1074

I have this tuple of functions and I am trying to reverse it.

    namespace Utils {
        export type IsFinite<Tuple extends any[], Finite, Infinite> = {
            empty: Finite
            nonEmpty: ((..._: Tuple) => any) extends ((_: infer First, ..._1: infer Rest) => any)
            ? IsFinite<Rest, Finite, Infinite>
            : never
            infinite: Infinite
        }[
            Tuple extends [] ? 'empty' :
            Tuple extends (infer Element)[] ?
            Element[] extends Tuple ?
            'infinite'
            : 'nonEmpty'
            : never
        ]

        export type Prepend<Tuple extends any[], Addend> =
            ((_: Addend, ..._1: Tuple) => any) extends ((..._: infer Result) => any) ? Result : never


        export type Reverse<Tuple extends any[], Prefix extends any[] = []> = {
            empty: Prefix,
            nonEmpty: ((..._: Tuple) => any) extends ((_: infer First, ..._1: infer Next) => any)
            ? Reverse<Next, Prepend<Prefix, First>>
            : never
            infinite: {
                ERROR: 'Cannot reverse an infinite tuple'
                CODENAME: 'InfiniteTuple'
            }
        }[
            Tuple extends [any, ...any[]]
            ? IsFinite<Tuple, 'nonEmpty', 'infinite'>
            : 'empty'
        ]
    }

    export type ReadFuncs = readonly ((x: any) => any)[]
    export type Reverse<Tuple extends ReadFuncs> = Utils.Reverse<Tuple>

Playground

With TS 3.4 it became common practice to create tuples with [a, b, c] as const. This is really convenient, however the resulting tuple is readonly. It would be awesome to add support for these readonly tuples, right now I get error readonly (something) is not assignable to any[].

warning [email protected]: The engine "typescript" appears to be invalid.

Currently I'm getting this issue because you declare here:

"engines": { "typescript": "^3.0.0" }

in the package.json file.

https://docs.npmjs.com/files/package.json#engines
Please take a look at this official documentation, apparently TS should not be used here.

This library was added to my project after updating another library dependency. I am using v2.2.1. I get a Type expected error from this library when building my source on the following lines:

typescript-tuple/lib/index.d.ts(19,47)
typescript-tuple/lib/index.d.ts(156,60)
typescript-tuple/lib/index.d.ts(161,59)
typescript-tuple/lib/utils.d.ts(13,87)
typescript-tuple/lib/utils.d.ts(64,23)

What causes this? Is the issue fixed in a newer release?

Feature request

Ive recently been looking for ages to find a type-save implementation of recursively plucking an object via a tuple (explaination below). As I was unable to find any solution online, I resorted to posting a stackoverflow question which was answered brilliantly by @maciejsikora very recently.

Would you be open to adopting this type here? Before diving in to the depths of the internet to find a solution for my problem, I was aware of typescript-tuple (searching typescript-tuple was actually the first thing I did when researching). Hence my request to adopt it here. I understand if you consider this off topic here, since it is not purely of tuple domain. If so, Id gald if you could point me in a direction (maybe another library) where this feature would be better suited.

type Test1 = RecursivePluck<{a: {b: {c: {e: string}}, d: string}}, ['a','d']> // typeof string
type Test2 = RecursivePluck<{a: {b: {c: string}, d: string}},['a', 'b']> // typeof {c: string}

Here the implemantation by @maciejsikora.

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These updates have all been created already. Click a checkbox below to force a retry/rebase of any.

• Update dependency typescript to ~4.9.0

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https://github.com/eigenmethod/mol/tree/master/type

	type should_be_same_but_without_head = Assert<
		Tail< [ 666 , 777 ] > ,
		[ 777 ]
	>

Can I somehow write a function "append" that takes a random tuple and appends something to it?

Example:

append([1,'2',3], true) // should be [1,'2',3,true]
append([], 1) // should be [1]

I have tried something like this:

function append<A extends any[], V>(a: A, v: V): Append<A, V>;

but I keep receiving "Infinite Tuple" Error.

I was wondering if you could help me.

I attempted implementing reverse. For some reason the types work sometimes in a straight forward manner ( see reverse1 below ) and sometimes backwards ( see reverse2 ). Is this a bug or is this how it is supposed to work?

function reverse1<A extends Array<any>>(a: A): Reverse<A> {
  return (a.reverse() as unknown) as Reverse<A>;
}

function reverse2<A extends Array<any>>(a: Reverse<A>): A {
  return (a.reverse() as unknown) as A;
}