<const T2 extends ReadonlyArray<unknown>>(that: T2): <
const T1 extends ReadonlyArray<unknown>
>(
self: T1
) => [...T1, ...T2]
<
const T1 extends ReadonlyArray<unknown>,
const T2 extends ReadonlyArray<unknown>
>(
self: T1,
that: T2
): [...T1, ...T2]Concatenates two tuples into a single tuple.
When to use
Use to append all elements from one tuple to another tuple.
Details
The result type is [...T1, ...T2], preserving all element types from both
tuples. Neither input tuple is mutated; a fresh tuple is returned.
Example (Concatenating tuples)
import { pipe, Tuple } from "effect"
const result = pipe(Tuple.make(1, 2), Tuple.appendElements(["a", "b"] as const))
console.log(result) // [1, 2, "a", "b"]combiningappendElement
Source effect/Tuple.ts:24012 lines
export const const appendElements: {
<const T2 extends ReadonlyArray<unknown>>(
that: T2
): <const T1 extends ReadonlyArray<unknown>>(
self: T1
) => [...T1, ...T2]
<
const T1 extends ReadonlyArray<unknown>,
const T2 extends ReadonlyArray<unknown>
>(
self: T1,
that: T2
): [...T1, ...T2]
}
Concatenates two tuples into a single tuple.
When to use
Use to append all elements from one tuple to another tuple.
Details
The result type is [...T1, ...T2], preserving all element types from both
tuples. Neither input tuple is mutated; a fresh tuple is returned.
Example (Concatenating tuples)
import { pipe, Tuple } from "effect"
const result = pipe(Tuple.make(1, 2), Tuple.appendElements(["a", "b"] as const))
console.log(result) // [1, 2, "a", "b"]
appendElements: {
<const function (type parameter) T2 in <const T2 extends ReadonlyArray<unknown>>(that: T2): <const T1 extends ReadonlyArray<unknown>>(self: T1) => [...T1, ...T2]T2 extends interface ReadonlyArray<T>ReadonlyArray<unknown>>(
that: const T2 extends ReadonlyArray<unknown>that: function (type parameter) T2 in <const T2 extends ReadonlyArray<unknown>>(that: T2): <const T1 extends ReadonlyArray<unknown>>(self: T1) => [...T1, ...T2]T2
): <const function (type parameter) T1 in <const T1 extends ReadonlyArray<unknown>>(self: T1): [...T1, ...T2]T1 extends interface ReadonlyArray<T>ReadonlyArray<unknown>>(self: const T1 extends ReadonlyArray<unknown>self: function (type parameter) T1 in <const T1 extends ReadonlyArray<unknown>>(self: T1): [...T1, ...T2]T1) => [...function (type parameter) T1 in <const T1 extends ReadonlyArray<unknown>>(self: T1): [...T1, ...T2]T1, ...function (type parameter) T2 in <const T2 extends ReadonlyArray<unknown>>(that: T2): <const T1 extends ReadonlyArray<unknown>>(self: T1) => [...T1, ...T2]T2]
<const function (type parameter) T1 in <const T1 extends ReadonlyArray<unknown>, const T2 extends ReadonlyArray<unknown>>(self: T1, that: T2): [...T1, ...T2]T1 extends interface ReadonlyArray<T>ReadonlyArray<unknown>, const function (type parameter) T2 in <const T1 extends ReadonlyArray<unknown>, const T2 extends ReadonlyArray<unknown>>(self: T1, that: T2): [...T1, ...T2]T2 extends interface ReadonlyArray<T>ReadonlyArray<unknown>>(self: const T1 extends ReadonlyArray<unknown>self: function (type parameter) T1 in <const T1 extends ReadonlyArray<unknown>, const T2 extends ReadonlyArray<unknown>>(self: T1, that: T2): [...T1, ...T2]T1, that: const T2 extends ReadonlyArray<unknown>that: function (type parameter) T2 in <const T1 extends ReadonlyArray<unknown>, const T2 extends ReadonlyArray<unknown>>(self: T1, that: T2): [...T1, ...T2]T2): [...function (type parameter) T1 in <const T1 extends ReadonlyArray<unknown>, const T2 extends ReadonlyArray<unknown>>(self: T1, that: T2): [...T1, ...T2]T1, ...function (type parameter) T2 in <const T1 extends ReadonlyArray<unknown>, const T2 extends ReadonlyArray<unknown>>(self: T1, that: T2): [...T1, ...T2]T2]
} = dual<(...args: Array<any>) => any, <T1 extends ReadonlyArray<unknown>, T2 extends ReadonlyArray<unknown>>(self: T1, that: T2) => [...T1, ...T2]>(arity: 2, body: <T1 extends ReadonlyArray<unknown>, T2 extends ReadonlyArray<unknown>>(self: T1, that: T2) => [...T1, ...T2]): ((...args: Array<any>) => any) & (<T1 extends ReadonlyArray<unknown>, T2 extends ReadonlyArray<unknown>>(self: T1, that: T2) => [...T1, ...T2]) (+1 overload)Creates a function that can be called in data-first style or data-last
(pipe-friendly) style.
When to use
Use to expose one implementation through both direct and pipe-friendly
call styles.
Details
Pass either the arity of the uncurried function or a predicate that decides
whether the current call is data-first. Arity is the common case. Use a
predicate when optional arguments make arity ambiguous.
Example (Selecting data-first or data-last style by arity)
import { Function, pipe } from "effect"
const sum = Function.dual<
(that: number) => (self: number) => number,
(self: number, that: number) => number
>(2, (self, that) => self + that)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
Example (Defining overloads with call signatures)
import { Function, pipe } from "effect"
const sum: {
(that: number): (self: number) => number
(self: number, that: number): number
} = Function.dual(2, (self: number, that: number): number => self + that)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
Example (Selecting data-first or data-last style with a predicate)
import { Function, pipe } from "effect"
const sum = Function.dual<
(that: number) => (self: number) => number,
(self: number, that: number) => number
>(
(args) => args.length === 2,
(self, that) => self + that
)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
dual(
2,
<function (type parameter) T1 in <T1 extends ReadonlyArray<unknown>, T2 extends ReadonlyArray<unknown>>(self: T1, that: T2): [...T1, ...T2]T1 extends interface ReadonlyArray<T>ReadonlyArray<unknown>, function (type parameter) T2 in <T1 extends ReadonlyArray<unknown>, T2 extends ReadonlyArray<unknown>>(self: T1, that: T2): [...T1, ...T2]T2 extends interface ReadonlyArray<T>ReadonlyArray<unknown>>(
self: T1 extends ReadonlyArray<unknown>self: function (type parameter) T1 in <T1 extends ReadonlyArray<unknown>, T2 extends ReadonlyArray<unknown>>(self: T1, that: T2): [...T1, ...T2]T1,
that: T2 extends ReadonlyArray<unknown>that: function (type parameter) T2 in <T1 extends ReadonlyArray<unknown>, T2 extends ReadonlyArray<unknown>>(self: T1, that: T2): [...T1, ...T2]T2
): [...function (type parameter) T1 in <T1 extends ReadonlyArray<unknown>, T2 extends ReadonlyArray<unknown>>(self: T1, that: T2): [...T1, ...T2]T1, ...function (type parameter) T2 in <T1 extends ReadonlyArray<unknown>, T2 extends ReadonlyArray<unknown>>(self: T1, that: T2): [...T1, ...T2]T2] => [...self: T1 extends ReadonlyArray<unknown>self, ...that: T2 extends ReadonlyArray<unknown>that]
)