<S extends Iterable<any>, T extends Iterable<any>>(that: T): (
self: S
) => ReadonlyArray.OrNonEmpty<
S,
T,
ReadonlyArray.Infer<S> | ReadonlyArray.Infer<T>
>
<A, B>(self: Iterable<A>, that: NonEmptyReadonlyArray<B>): NonEmptyArray<
A | B
>
<A, B>(self: NonEmptyReadonlyArray<A>, that: Iterable<B>): NonEmptyArray<
A | B
>
<A, B>(self: Iterable<A>, that: Iterable<B>): Array<A | B>Prepends all elements from a prefix iterable to the front of an array.
When to use
Use to prepend multiple elements from an iterable to the front of an array.
Details
If either input is non-empty, the result is a NonEmptyArray.
Example (Prepending multiple elements)
import { Array } from "effect"
const result = Array.prependAll([2, 3], [0, 1])
console.log(result) // [0, 1, 2, 3]Source effect/Array.ts:60911 lines
export const const prependAll: {
<
S extends Iterable<any>,
T extends Iterable<any>
>(
that: T
): (
self: S
) => ReadonlyArray.OrNonEmpty<
S,
T,
| ReadonlyArray.Infer<S>
| ReadonlyArray.Infer<T>
>
<A, B>(
self: Iterable<A>,
that: NonEmptyReadonlyArray<B>
): NonEmptyArray<A | B>
<A, B>(
self: NonEmptyReadonlyArray<A>,
that: Iterable<B>
): NonEmptyArray<A | B>
<A, B>(
self: Iterable<A>,
that: Iterable<B>
): Array<A | B>
}
Prepends all elements from a prefix iterable to the front of an array.
When to use
Use to prepend multiple elements from an iterable to the front of an array.
Details
If either input is non-empty, the result is a NonEmptyArray.
Example (Prepending multiple elements)
import { Array } from "effect"
const result = Array.prependAll([2, 3], [0, 1])
console.log(result) // [0, 1, 2, 3]
prependAll: {
<function (type parameter) S in <S extends Iterable<any>, T extends Iterable<any>>(that: T): (self: S) => ReadonlyArray.OrNonEmpty<S, T, ReadonlyArray.Infer<S> | ReadonlyArray.Infer<T>>S extends interface Iterable<T, TReturn = any, TNext = any>Iterable<any>, function (type parameter) T in <S extends Iterable<any>, T extends Iterable<any>>(that: T): (self: S) => ReadonlyArray.OrNonEmpty<S, T, ReadonlyArray.Infer<S> | ReadonlyArray.Infer<T>>T extends interface Iterable<T, TReturn = any, TNext = any>Iterable<any>>(
that: T extends Iterable<any>that: function (type parameter) T in <S extends Iterable<any>, T extends Iterable<any>>(that: T): (self: S) => ReadonlyArray.OrNonEmpty<S, T, ReadonlyArray.Infer<S> | ReadonlyArray.Infer<T>>T
): (self: S extends Iterable<any>self: function (type parameter) S in <S extends Iterable<any>, T extends Iterable<any>>(that: T): (self: S) => ReadonlyArray.OrNonEmpty<S, T, ReadonlyArray.Infer<S> | ReadonlyArray.Infer<T>>S) => ReadonlyArray.type ReadonlyArray.OrNonEmpty<S extends Iterable<any>, T extends Iterable<any>, A> = S extends readonly [any, ...any[]] ? [A, ...A[]] : T extends readonly [any, ...any[]] ? [A, ...A[]] : A[]Creates a non-empty array if either input is non-empty.
Example (Preserving non-emptiness from either input)
import type { Array } from "effect"
type Result = Array.ReadonlyArray.OrNonEmpty<
readonly [number],
ReadonlyArray<string>,
number
>
// Result is NonEmptyArray<number>
OrNonEmpty<function (type parameter) S in <S extends Iterable<any>, T extends Iterable<any>>(that: T): (self: S) => ReadonlyArray.OrNonEmpty<S, T, ReadonlyArray.Infer<S> | ReadonlyArray.Infer<T>>S, function (type parameter) T in <S extends Iterable<any>, T extends Iterable<any>>(that: T): (self: S) => ReadonlyArray.OrNonEmpty<S, T, ReadonlyArray.Infer<S> | ReadonlyArray.Infer<T>>T, ReadonlyArray.type ReadonlyArray.Infer<S extends Iterable<any>> = S extends readonly (infer A)[] ? A : S extends Iterable<infer A> ? A : neverInfers the element type of an iterable.
Example (Inferring an element type)
import type { Array } from "effect"
type StringArrayType = Array.ReadonlyArray.Infer<ReadonlyArray<string>>
// StringArrayType is string
Infer<function (type parameter) S in <S extends Iterable<any>, T extends Iterable<any>>(that: T): (self: S) => ReadonlyArray.OrNonEmpty<S, T, ReadonlyArray.Infer<S> | ReadonlyArray.Infer<T>>S> | ReadonlyArray.type ReadonlyArray.Infer<S extends Iterable<any>> = S extends readonly (infer A)[] ? A : S extends Iterable<infer A> ? A : neverInfers the element type of an iterable.
Example (Inferring an element type)
import type { Array } from "effect"
type StringArrayType = Array.ReadonlyArray.Infer<ReadonlyArray<string>>
// StringArrayType is string
Infer<function (type parameter) T in <S extends Iterable<any>, T extends Iterable<any>>(that: T): (self: S) => ReadonlyArray.OrNonEmpty<S, T, ReadonlyArray.Infer<S> | ReadonlyArray.Infer<T>>T>>
<function (type parameter) A in <A, B>(self: Iterable<A>, that: NonEmptyReadonlyArray<B>): NonEmptyArray<A | B>A, function (type parameter) B in <A, B>(self: Iterable<A>, that: NonEmptyReadonlyArray<B>): NonEmptyArray<A | B>B>(self: Iterable<A>self: interface Iterable<T, TReturn = any, TNext = any>Iterable<function (type parameter) A in <A, B>(self: Iterable<A>, that: NonEmptyReadonlyArray<B>): NonEmptyArray<A | B>A>, that: NonEmptyReadonlyArray<B>(parameter) that: {
0: B;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<B>>): Array<B>; (...items: Array<B | ConcatArray<B>>): Array<B> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<B>;
indexOf: (searchElement: B, fromIndex?: number) => number;
lastIndexOf: (searchElement: B, fromIndex?: number) => number;
every: { (predicate: (value: B, index: number, array: ReadonlyArray<B>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: B, index: number, array: ReadonlyArray<B>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: B, index: number, array: ReadonlyArray<B>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: B, index: number, array: ReadonlyArray<B>) => void, thisArg?: any) => void;
map: (callbackfn: (value: B, index: number, array: ReadonlyArray<B>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: B, index: number, array: ReadonlyArray<B>) => value is S, thisArg?: any): Array<S>; (predicate: (value: B, index: number, array: ReadonlyArray<B>) => unknown, thisArg?: any): Array<B> };
reduce: { (callbackfn: (previousValue: B, currentValue: B, currentIndex: number, array: ReadonlyArray<B>) => B): B; (callbackfn: (previousValue: B, currentValue: B, currentIndex: number, array: ReadonlyArray<B>) => B, initialValue: B): B; (callbac…;
reduceRight: { (callbackfn: (previousValue: B, currentValue: B, currentIndex: number, array: ReadonlyArray<B>) => B): B; (callbackfn: (previousValue: B, currentValue: B, currentIndex: number, array: ReadonlyArray<B>) => B, initialValue: B): B; (callbac…;
find: { (predicate: (value: B, index: number, obj: ReadonlyArray<B>) => value is S, thisArg?: any): S | undefined; (predicate: (value: B, index: number, obj: ReadonlyArray<B>) => unknown, thisArg?: any): B | undefined };
findIndex: (predicate: (value: B, index: number, obj: ReadonlyArray<B>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, B]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<B>;
includes: (searchElement: B, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: B, index: number, array: Array<B>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => B | undefined;
findLast: { (predicate: (value: B, index: number, array: ReadonlyArray<B>) => value is S, thisArg?: any): S | undefined; (predicate: (value: B, index: number, array: ReadonlyArray<B>) => unknown, thisArg?: any): B | undefined };
findLastIndex: (predicate: (value: B, index: number, array: ReadonlyArray<B>) => unknown, thisArg?: any) => number;
toReversed: () => Array<B>;
toSorted: (compareFn?: ((a: B, b: B) => number) | undefined) => Array<B>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<B>): Array<B>; (start: number, deleteCount?: number): Array<B> };
with: (index: number, value: B) => Array<B>;
}
type NonEmptyReadonlyArray<A> = readonly [
A,
...A[]
]
A readonly array guaranteed to have at least one element.
When to use
Use when non-emptiness must be tracked at the type level while preventing mutation.
Many Array module functions accept or return this type.
Example (Typing a non-empty array)
import type { Array } from "effect"
const nonEmpty: Array.NonEmptyReadonlyArray<number> = [1, 2, 3]
const head: number = nonEmpty[0] // guaranteed to exist
NonEmptyReadonlyArray<function (type parameter) B in <A, B>(self: Iterable<A>, that: NonEmptyReadonlyArray<B>): NonEmptyArray<A | B>B>): type NonEmptyArray<A> = [A, ...A[]]A mutable array guaranteed to have at least one element.
When to use
Use when mutation is acceptable and non-emptiness must be tracked at the type
level.
Details
This is the mutable counterpart of
NonEmptyReadonlyArray
. Most Array
module functions return NonEmptyArray when the result is guaranteed
non-empty.
Example (Typing a mutable non-empty array)
import type { Array } from "effect"
const nonEmpty: Array.NonEmptyArray<number> = [1, 2, 3]
nonEmpty.push(4)
NonEmptyArray<function (type parameter) A in <A, B>(self: Iterable<A>, that: NonEmptyReadonlyArray<B>): NonEmptyArray<A | B>A | function (type parameter) B in <A, B>(self: Iterable<A>, that: NonEmptyReadonlyArray<B>): NonEmptyArray<A | B>B>
<function (type parameter) A in <A, B>(self: NonEmptyReadonlyArray<A>, that: Iterable<B>): NonEmptyArray<A | B>A, function (type parameter) B in <A, B>(self: NonEmptyReadonlyArray<A>, that: Iterable<B>): NonEmptyArray<A | B>B>(self: NonEmptyReadonlyArray<A>(parameter) self: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<A>;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
find: { (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, A]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<A>;
includes: (searchElement: A, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: A, index: number, array: Array<A>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => A | undefined;
findLast: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
toReversed: () => Array<A>;
toSorted: (compareFn?: ((a: A, b: A) => number) | undefined) => Array<A>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<A>): Array<A>; (start: number, deleteCount?: number): Array<A> };
with: (index: number, value: A) => Array<A>;
}
type NonEmptyReadonlyArray<A> = readonly [
A,
...A[]
]
A readonly array guaranteed to have at least one element.
When to use
Use when non-emptiness must be tracked at the type level while preventing mutation.
Many Array module functions accept or return this type.
Example (Typing a non-empty array)
import type { Array } from "effect"
const nonEmpty: Array.NonEmptyReadonlyArray<number> = [1, 2, 3]
const head: number = nonEmpty[0] // guaranteed to exist
NonEmptyReadonlyArray<function (type parameter) A in <A, B>(self: NonEmptyReadonlyArray<A>, that: Iterable<B>): NonEmptyArray<A | B>A>, that: Iterable<B>that: interface Iterable<T, TReturn = any, TNext = any>Iterable<function (type parameter) B in <A, B>(self: NonEmptyReadonlyArray<A>, that: Iterable<B>): NonEmptyArray<A | B>B>): type NonEmptyArray<A> = [A, ...A[]]A mutable array guaranteed to have at least one element.
When to use
Use when mutation is acceptable and non-emptiness must be tracked at the type
level.
Details
This is the mutable counterpart of
NonEmptyReadonlyArray
. Most Array
module functions return NonEmptyArray when the result is guaranteed
non-empty.
Example (Typing a mutable non-empty array)
import type { Array } from "effect"
const nonEmpty: Array.NonEmptyArray<number> = [1, 2, 3]
nonEmpty.push(4)
NonEmptyArray<function (type parameter) A in <A, B>(self: NonEmptyReadonlyArray<A>, that: Iterable<B>): NonEmptyArray<A | B>A | function (type parameter) B in <A, B>(self: NonEmptyReadonlyArray<A>, that: Iterable<B>): NonEmptyArray<A | B>B>
<function (type parameter) A in <A, B>(self: Iterable<A>, that: Iterable<B>): Array<A | B>A, function (type parameter) B in <A, B>(self: Iterable<A>, that: Iterable<B>): Array<A | B>B>(self: Iterable<A>self: interface Iterable<T, TReturn = any, TNext = any>Iterable<function (type parameter) A in <A, B>(self: Iterable<A>, that: Iterable<B>): Array<A | B>A>, that: Iterable<B>that: interface Iterable<T, TReturn = any, TNext = any>Iterable<function (type parameter) B in <A, B>(self: Iterable<A>, that: Iterable<B>): Array<A | B>B>): interface Array<T>Array<function (type parameter) A in <A, B>(self: Iterable<A>, that: Iterable<B>): Array<A | B>A | function (type parameter) B in <A, B>(self: Iterable<A>, that: Iterable<B>): Array<A | B>B>
} = dual<(...args: Array<any>) => any, <A>(self: Iterable<A>, that: Iterable<A>) => Array<A>>(arity: 2, body: <A>(self: Iterable<A>, that: Iterable<A>) => Array<A>): ((...args: Array<any>) => any) & (<A>(self: Iterable<A>, that: Iterable<A>) => Array<A>) (+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) A in <A>(self: Iterable<A>, that: Iterable<A>): Array<A>A>(self: Iterable<A>self: interface Iterable<T, TReturn = any, TNext = any>Iterable<function (type parameter) A in <A>(self: Iterable<A>, that: Iterable<A>): Array<A>A>, that: Iterable<A>that: interface Iterable<T, TReturn = any, TNext = any>Iterable<function (type parameter) A in <A>(self: Iterable<A>, that: Iterable<A>): Array<A>A>): interface Array<T>Array<function (type parameter) A in <A>(self: Iterable<A>, that: Iterable<A>): Array<A>A> => const fromIterable: <A>(
collection: Iterable<A>
) => A[]
Converts an Iterable to an Array.
When to use
Use to convert any Iterable (Set, Generator, etc.) into an array.
Details
If the input is already an array, this returns it by reference without
copying. Otherwise, it creates a new array from the iterable. Use copy if
you need a fresh array even when the input is already an array.
Example (Converting a Set to an array)
import { Array } from "effect"
const result = Array.fromIterable(new Set([1, 2, 3]))
console.log(result) // [1, 2, 3]
fromIterable(that: Iterable<A>that).Array<A>.concat(...items: ConcatArray<A>[]): A[] (+1 overload)Combines two or more arrays.
This method returns a new array without modifying any existing arrays.
concat(const fromIterable: <A>(
collection: Iterable<A>
) => A[]
Converts an Iterable to an Array.
When to use
Use to convert any Iterable (Set, Generator, etc.) into an array.
Details
If the input is already an array, this returns it by reference without
copying. Otherwise, it creates a new array from the iterable. Use copy if
you need a fresh array even when the input is already an array.
Example (Converting a Set to an array)
import { Array } from "effect"
const result = Array.fromIterable(new Set([1, 2, 3]))
console.log(result) // [1, 2, 3]
fromIterable(self: Iterable<A>self))
)