<S extends Iterable<any>, B>(
f: (a: ReadonlyArray.Infer<S>) => B,
order: Order.Order<B>
): (self: S) => ReadonlyArray.With<S, ReadonlyArray.Infer<S>>
<A, B>(
self: NonEmptyReadonlyArray<A>,
f: (a: A) => B,
O: Order.Order<B>
): NonEmptyArray<A>
<A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>Sorts an array by a derived key using a mapping function and an Order for
that key.
When to use
Use when you need to sort values by a derived key, such as a string length or object field, while keeping the original values.
Details
Equivalent to sort(Order.mapInput(order, f)), but more convenient.
Example (Sorting strings by length)
import { Array, Order } from "effect"
console.log(Array.sortWith(["aaa", "b", "cc"], (s) => s.length, Order.Number))
// ["b", "cc", "aaa"]export const const sortWith: {
<S extends Iterable<any>, B>(
f: (a: ReadonlyArray.Infer<S>) => B,
order: Order.Order<B>
): (
self: S
) => ReadonlyArray.With<
S,
ReadonlyArray.Infer<S>
>
<A, B>(
self: NonEmptyReadonlyArray<A>,
f: (a: A) => B,
O: Order.Order<B>
): NonEmptyArray<A>
<A, B>(
self: Iterable<A>,
f: (a: A) => B,
order: Order.Order<B>
): Array<A>
}
Sorts an array by a derived key using a mapping function and an Order for
that key.
When to use
Use when you need to sort values by a derived key, such as a string length or
object field, while keeping the original values.
Details
Equivalent to sort(Order.mapInput(order, f)), but more convenient.
Example (Sorting strings by length)
import { Array, Order } from "effect"
console.log(Array.sortWith(["aaa", "b", "cc"], (s) => s.length, Order.Number))
// ["b", "cc", "aaa"]
sortWith: {
<function (type parameter) S in <S extends Iterable<any>, B>(f: (a: ReadonlyArray.Infer<S>) => B, order: Order.Order<B>): (self: S) => ReadonlyArray.With<S, ReadonlyArray.Infer<S>>S extends interface Iterable<T, TReturn = any, TNext = any>Iterable<any>, function (type parameter) B in <S extends Iterable<any>, B>(f: (a: ReadonlyArray.Infer<S>) => B, order: Order.Order<B>): (self: S) => ReadonlyArray.With<S, ReadonlyArray.Infer<S>>B>(
f: (a: ReadonlyArray.Infer<S>) => Bf: (a: ReadonlyArray.Infer<S>a: 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>, B>(f: (a: ReadonlyArray.Infer<S>) => B, order: Order.Order<B>): (self: S) => ReadonlyArray.With<S, ReadonlyArray.Infer<S>>S>) => function (type parameter) B in <S extends Iterable<any>, B>(f: (a: ReadonlyArray.Infer<S>) => B, order: Order.Order<B>): (self: S) => ReadonlyArray.With<S, ReadonlyArray.Infer<S>>B,
order: Order.Order<B>order: import OrderOrder.interface Order<in A>Represents a total ordering for values of type A.
When to use
Use when you need to define how values of a type are compared.
Details
An order returns -1 when the first value is less than the second, 0 when
the values are equal according to this ordering, and 1 when the first value
is greater than the second. It must satisfy total ordering laws: totality,
antisymmetry, and transitivity.
Example (Defining a custom Order)
import { Order } from "effect"
const byAge: Order.Order<{ name: string; age: number }> = (self, that) => {
if (self.age < that.age) return -1
if (self.age > that.age) return 1
return 0
}
const person1 = { name: "Alice", age: 30 }
const person2 = { name: "Bob", age: 25 }
console.log(byAge(person1, person2)) // 1
Order<function (type parameter) B in <S extends Iterable<any>, B>(f: (a: ReadonlyArray.Infer<S>) => B, order: Order.Order<B>): (self: S) => ReadonlyArray.With<S, ReadonlyArray.Infer<S>>B>
): (self: S extends Iterable<any>self: function (type parameter) S in <S extends Iterable<any>, B>(f: (a: ReadonlyArray.Infer<S>) => B, order: Order.Order<B>): (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>, B>(f: (a: ReadonlyArray.Infer<S>) => B, order: Order.Order<B>): (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>, B>(f: (a: ReadonlyArray.Infer<S>) => B, order: Order.Order<B>): (self: S) => ReadonlyArray.With<S, ReadonlyArray.Infer<S>>S>>
<function (type parameter) A in <A, B>(self: NonEmptyReadonlyArray<A>, f: (a: A) => B, O: Order.Order<B>): NonEmptyArray<A>A, function (type parameter) B in <A, B>(self: NonEmptyReadonlyArray<A>, f: (a: A) => B, O: Order.Order<B>): NonEmptyArray<A>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>, f: (a: A) => B, O: Order.Order<B>): NonEmptyArray<A>A>, f: (a: A) => Bf: (a: Aa: function (type parameter) A in <A, B>(self: NonEmptyReadonlyArray<A>, f: (a: A) => B, O: Order.Order<B>): NonEmptyArray<A>A) => function (type parameter) B in <A, B>(self: NonEmptyReadonlyArray<A>, f: (a: A) => B, O: Order.Order<B>): NonEmptyArray<A>B, type O: Order.Order<B>O: import OrderOrder.interface Order<in A>Represents a total ordering for values of type A.
When to use
Use when you need to define how values of a type are compared.
Details
An order returns -1 when the first value is less than the second, 0 when
the values are equal according to this ordering, and 1 when the first value
is greater than the second. It must satisfy total ordering laws: totality,
antisymmetry, and transitivity.
Example (Defining a custom Order)
import { Order } from "effect"
const byAge: Order.Order<{ name: string; age: number }> = (self, that) => {
if (self.age < that.age) return -1
if (self.age > that.age) return 1
return 0
}
const person1 = { name: "Alice", age: 30 }
const person2 = { name: "Bob", age: 25 }
console.log(byAge(person1, person2)) // 1
Order<function (type parameter) B in <A, B>(self: NonEmptyReadonlyArray<A>, f: (a: A) => B, O: Order.Order<B>): NonEmptyArray<A>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>, f: (a: A) => B, O: Order.Order<B>): NonEmptyArray<A>A>
<function (type parameter) A in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>A, function (type parameter) B in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>B>(self: Iterable<A>self: interface Iterable<T, TReturn = any, TNext = any>Iterable<function (type parameter) A in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>A>, f: (a: A) => Bf: (a: Aa: function (type parameter) A in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>A) => function (type parameter) B in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>B, order: Order.Order<B>order: import OrderOrder.interface Order<in A>Represents a total ordering for values of type A.
When to use
Use when you need to define how values of a type are compared.
Details
An order returns -1 when the first value is less than the second, 0 when
the values are equal according to this ordering, and 1 when the first value
is greater than the second. It must satisfy total ordering laws: totality,
antisymmetry, and transitivity.
Example (Defining a custom Order)
import { Order } from "effect"
const byAge: Order.Order<{ name: string; age: number }> = (self, that) => {
if (self.age < that.age) return -1
if (self.age > that.age) return 1
return 0
}
const person1 = { name: "Alice", age: 30 }
const person2 = { name: "Bob", age: 25 }
console.log(byAge(person1, person2)) // 1
Order<function (type parameter) B in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>B>): interface Array<T>Array<function (type parameter) A in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>A>
} = dual<(...args: Array<any>) => any, <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>) => Array<A>>(arity: 3, body: <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>) => Array<A>): ((...args: Array<any>) => any) & (<A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>) => 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(
3,
<function (type parameter) A in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>A, function (type parameter) B in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>B>(self: Iterable<A>self: interface Iterable<T, TReturn = any, TNext = any>Iterable<function (type parameter) A in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>A>, f: (a: A) => Bf: (a: Aa: function (type parameter) A in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>A) => function (type parameter) B in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>B, order: Order.Order<B>order: import OrderOrder.interface Order<in A>Represents a total ordering for values of type A.
When to use
Use when you need to define how values of a type are compared.
Details
An order returns -1 when the first value is less than the second, 0 when
the values are equal according to this ordering, and 1 when the first value
is greater than the second. It must satisfy total ordering laws: totality,
antisymmetry, and transitivity.
Example (Defining a custom Order)
import { Order } from "effect"
const byAge: Order.Order<{ name: string; age: number }> = (self, that) => {
if (self.age < that.age) return -1
if (self.age > that.age) return 1
return 0
}
const person1 = { name: "Alice", age: 30 }
const person2 = { name: "Bob", age: 25 }
console.log(byAge(person1, person2)) // 1
Order<function (type parameter) B in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>B>): interface Array<T>Array<function (type parameter) A in <A, B>(self: Iterable<A>, f: (a: A) => B, order: Order.Order<B>): Array<A>A> =>
const Array: ArrayConstructorExposes the global array constructor.
When to use
Use to access native JavaScript array constructor methods such as isArray
or from from the Effect module namespace.
Example (Accessing the Array constructor)
import { Array } from "effect"
const arr = new Array.Array(3)
console.log(arr) // [undefined, undefined, undefined]
Array.ArrayConstructor.from<A>(iterable: Iterable<A> | ArrayLike<A>): A[] (+3 overloads)Creates an array from an iterable object.
from(self: Iterable<A>self).Array<A>.map<readonly [A, B]>(callbackfn: (value: A, index: number, array: A[]) => readonly [A, B], thisArg?: any): (readonly [A, B])[]Calls a defined callback function on each element of an array, and returns an array that contains the results.
map((a: Aa) => [a: Aa, f: (a: A) => Bf(a: Aa)] as type const = readonly [A, B]const).Array<readonly [A, B]>.sort(compareFn?: ((a: readonly [A, B], b: readonly [A, B]) => number) | undefined): (readonly [A, B])[]Sorts an array in place.
This method mutates the array and returns a reference to the same array.
sort(([, a: Ba], [, b: Bb]) => order: Order.Order<B>order(a: Ba, b: Bb)).Array<readonly [A, B]>.map<A>(callbackfn: (value: readonly [A, B], index: number, array: (readonly [A, B])[]) => A, thisArg?: any): A[]Calls a defined callback function on each element of an array, and returns an array that contains the results.
map(([_: A_]) => _: A_)
)