(n: number): <S extends Iterable<any>>(
self: S
) => ReadonlyArray.With<S, ReadonlyArray.Infer<S>>
<A>(self: NonEmptyReadonlyArray<A>, n: number): NonEmptyArray<A>
<A>(self: Iterable<A>, n: number): Array<A>Transforms an array by rotating it n steps. Positive n rotates right; negative n
rotates left.
When to use
Use when elements should wrap around the end of the array rather than being dropped.
Details
n is rounded to the nearest integer before rotating. The return type
preserves NonEmptyArray. Empty arrays, or rotations normalized to 0,
return a copy.
Example (Rotating elements)
import { Array } from "effect"
console.log(Array.rotate(["a", "b", "c", "d"], 2)) // ["c", "d", "a", "b"]Source effect/Array.ts:249421 lines
export const const rotate: {
(n: number): <S extends Iterable<any>>(
self: S
) => ReadonlyArray.With<
S,
ReadonlyArray.Infer<S>
>
<A>(
self: NonEmptyReadonlyArray<A>,
n: number
): NonEmptyArray<A>
<A>(self: Iterable<A>, n: number): Array<A>
}
Transforms an array by rotating it n steps. Positive n rotates right; negative n
rotates left.
When to use
Use when elements should wrap around the end of the array rather than being
dropped.
Details
n is rounded to the nearest integer before rotating. The return type
preserves NonEmptyArray. Empty arrays, or rotations normalized to 0,
return a copy.
Example (Rotating elements)
import { Array } from "effect"
console.log(Array.rotate(["a", "b", "c", "d"], 2)) // ["c", "d", "a", "b"]
rotate: {
(n: numbern: number): <function (type parameter) S in <S extends Iterable<any>>(self: S): ReadonlyArray.With<S, ReadonlyArray.Infer<S>>S extends interface Iterable<T, TReturn = any, TNext = any>Iterable<any>>(self: S extends Iterable<any>self: function (type parameter) S in <S extends Iterable<any>>(self: S): ReadonlyArray.With<S, ReadonlyArray.Infer<S>>S) => ReadonlyArray.type ReadonlyArray.With<S extends Iterable<any>, A> = S extends readonly [any, ...any[]] ? [A, ...A[]] : A[]Constructs an array type preserving non-emptiness.
Example (Preserving non-emptiness)
import type { Array } from "effect"
type Result = Array.ReadonlyArray.With<readonly [number], string>
// Result is NonEmptyArray<string>
With<function (type parameter) S in <S extends Iterable<any>>(self: S): ReadonlyArray.With<S, ReadonlyArray.Infer<S>>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) S in <S extends Iterable<any>>(self: S): ReadonlyArray.With<S, ReadonlyArray.Infer<S>>S>>
<function (type parameter) A in <A>(self: NonEmptyReadonlyArray<A>, n: number): NonEmptyArray<A>A>(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>(self: NonEmptyReadonlyArray<A>, n: number): NonEmptyArray<A>A>, n: numbern: number): 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>(self: NonEmptyReadonlyArray<A>, n: number): NonEmptyArray<A>A>
<function (type parameter) A in <A>(self: Iterable<A>, n: number): Array<A>A>(self: Iterable<A>self: interface Iterable<T, TReturn = any, TNext = any>Iterable<function (type parameter) A in <A>(self: Iterable<A>, n: number): Array<A>A>, n: numbern: number): interface Array<T>Array<function (type parameter) A in <A>(self: Iterable<A>, n: number): Array<A>A>
} = dual<(...args: Array<any>) => any, <A>(self: Iterable<A>, n: number) => Array<A>>(arity: 2, body: <A>(self: Iterable<A>, n: number) => Array<A>): ((...args: Array<any>) => any) & (<A>(self: Iterable<A>, n: number) => 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>, n: number): Array<A>A>(self: Iterable<A>self: interface Iterable<T, TReturn = any, TNext = any>Iterable<function (type parameter) A in <A>(self: Iterable<A>, n: number): Array<A>A>, n: numbern: number): interface Array<T>Array<function (type parameter) A in <A>(self: Iterable<A>, n: number): Array<A>A> => {
const const input: A[]input = 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)
if (const isReadonlyArrayNonEmpty: <A>(
self: ReadonlyArray<A>
) => self is NonEmptyReadonlyArray<A>
Checks whether a ReadonlyArray is non-empty, narrowing the type to
NonEmptyReadonlyArray.
When to use
Use when you need to prove a readonly array has at least one element without
requiring mutable array methods afterward.
Example (Checking for a non-empty readonly array)
import { Array } from "effect"
console.log(Array.isReadonlyArrayNonEmpty([])) // false
console.log(Array.isReadonlyArrayNonEmpty([1, 2, 3])) // true
isReadonlyArrayNonEmpty(const input: A[]input)) {
const const len: numberlen = const input: A[] & readonly [A, ...A[]]input.Array<T>.length: numberGets or sets the length of the array. This is a number one higher than the highest index in the array.
length
const const m: numberm = var Math: MathAn intrinsic object that provides basic mathematics functionality and constants.
Math.Math.round(x: number): numberReturns a supplied numeric expression rounded to the nearest integer.
round(n: numbern) % const len: numberlen
if (function isOutOfBounds<A>(
i: number,
as: readonly A[]
): boolean
var Math: MathAn intrinsic object that provides basic mathematics functionality and constants.
Math.Math.abs(x: number): numberReturns the absolute value of a number (the value without regard to whether it is positive or negative).
For example, the absolute value of -5 is the same as the absolute value of 5.
abs(const m: numberm), const input: A[] & readonly [A, ...A[]]input) || const m: numberm === 0) {
return const copy: {
<A>(
self: NonEmptyReadonlyArray<A>
): NonEmptyArray<A>
<A>(self: ReadonlyArray<A>): Array<A>
}
const input: A[] & readonly [A, ...A[]]input)
}
if (const m: numberm < 0) {
const [const f: [A, ...A[]]const f: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
pop: () => A | undefined;
push: (...items: Array<A>) => number;
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
reverse: () => Array<A>;
shift: () => A | undefined;
slice: (start?: number, end?: number) => Array<A>;
sort: (compareFn?: ((a: A, b: A) => number) | undefined) => [A, ...A[]];
splice: { (start: number, deleteCount?: number): Array<A>; (start: number, deleteCount: number, ...items: Array<A>): Array<A> };
unshift: (...items: Array<A>) => number;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: Array<A>) => value is S, thisArg?: any): this is S[]; (predicate: (value: A, index: number, array: Array<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: Array<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: Array<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: Array<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: Array<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: Array<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: Array<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: Array<A>) => A, initialValue: A): A; (callbackfn: (previousVa…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: Array<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: Array<A>) => A, initialValue: A): A; (callbackfn: (previousVa…;
find: { (predicate: (value: A, index: number, obj: Array<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: Array<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: Array<A>) => unknown, thisArg?: any) => number;
fill: (value: A, start?: number, end?: number) => [A, ...A[]];
copyWithin: (target: number, start: number, end?: number) => [A, ...A[]];
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: Array<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: Array<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: Array<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>;
}
const s: A[]s] = const splitAtNonEmpty: {
(n: number): <A>(
self: NonEmptyReadonlyArray<A>
) => [
beforeIndex: NonEmptyArray<A>,
fromIndex: Array<A>
]
<A>(
self: NonEmptyReadonlyArray<A>,
n: number
): [
beforeIndex: NonEmptyArray<A>,
fromIndex: Array<A>
]
}
const input: A[] & readonly [A, ...A[]]input, -const m: numberm)
return const appendAll: {
<
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>
}
const s: A[]s, const f: [A, ...A[]]const f: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
pop: () => A | undefined;
push: (...items: Array<A>) => number;
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
reverse: () => Array<A>;
shift: () => A | undefined;
slice: (start?: number, end?: number) => Array<A>;
sort: (compareFn?: ((a: A, b: A) => number) | undefined) => [A, ...A[]];
splice: { (start: number, deleteCount?: number): Array<A>; (start: number, deleteCount: number, ...items: Array<A>): Array<A> };
unshift: (...items: Array<A>) => number;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: Array<A>) => value is S, thisArg?: any): this is S[]; (predicate: (value: A, index: number, array: Array<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: Array<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: Array<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: Array<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: Array<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: Array<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: Array<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: Array<A>) => A, initialValue: A): A; (callbackfn: (previousVa…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: Array<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: Array<A>) => A, initialValue: A): A; (callbackfn: (previousVa…;
find: { (predicate: (value: A, index: number, obj: Array<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: Array<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: Array<A>) => unknown, thisArg?: any) => number;
fill: (value: A, start?: number, end?: number) => [A, ...A[]];
copyWithin: (target: number, start: number, end?: number) => [A, ...A[]];
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: Array<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: Array<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: Array<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>;
}
const rotate: {
(n: number): <S extends Iterable<any>>(
self: S
) => ReadonlyArray.With<
S,
ReadonlyArray.Infer<S>
>
<A>(
self: NonEmptyReadonlyArray<A>,
n: number
): NonEmptyArray<A>
<A>(self: Iterable<A>, n: number): Array<A>
}
self: Iterable<A>self, const m: numberm - const len: numberlen)
}
}
return []
})