<B, A>(b: B, f: (b: B, a: A, i: number) => B): (self: Iterable<A>) => B
<A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BFolds an iterable from right to left into a single value.
When to use
Use when you need to fold values from right to left.
Details
The function receives (accumulator, element, index).
Example (Folding from right to left)
import { Array } from "effect"
console.log(Array.reduceRight([1, 2, 3], 0, (acc, n) => acc + n)) // 6export const const reduceRight: {
<B, A>(b: B, f: (b: B, a: A, i: number) => B): (
self: Iterable<A>
) => B
<A, B>(
self: Iterable<A>,
b: B,
f: (b: B, a: A, i: number) => B
): B
}
Folds an iterable from right to left into a single value.
When to use
Use when you need to fold values from right to left.
Details
The function receives (accumulator, element, index).
Example (Folding from right to left)
import { Array } from "effect"
console.log(Array.reduceRight([1, 2, 3], 0, (acc, n) => acc + n)) // 6
reduceRight: {
<function (type parameter) B in <B, A>(b: B, f: (b: B, a: A, i: number) => B): (self: Iterable<A>) => BB, function (type parameter) A in <B, A>(b: B, f: (b: B, a: A, i: number) => B): (self: Iterable<A>) => BA>(b: Bb: function (type parameter) B in <B, A>(b: B, f: (b: B, a: A, i: number) => B): (self: Iterable<A>) => BB, f: (b: B, a: A, i: number) => Bf: (b: Bb: function (type parameter) B in <B, A>(b: B, f: (b: B, a: A, i: number) => B): (self: Iterable<A>) => BB, a: Aa: function (type parameter) A in <B, A>(b: B, f: (b: B, a: A, i: number) => B): (self: Iterable<A>) => BA, i: numberi: number) => function (type parameter) B in <B, A>(b: B, f: (b: B, a: A, i: number) => B): (self: Iterable<A>) => BB): (self: Iterable<A>self: interface Iterable<T, TReturn = any, TNext = any>Iterable<function (type parameter) A in <B, A>(b: B, f: (b: B, a: A, i: number) => B): (self: Iterable<A>) => BA>) => function (type parameter) B in <B, A>(b: B, f: (b: B, a: A, i: number) => B): (self: Iterable<A>) => BB
<function (type parameter) A in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BA, function (type parameter) B in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BB>(self: Iterable<A>self: interface Iterable<T, TReturn = any, TNext = any>Iterable<function (type parameter) A in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BA>, b: Bb: function (type parameter) B in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BB, f: (b: B, a: A, i: number) => Bf: (b: Bb: function (type parameter) B in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BB, a: Aa: function (type parameter) A in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BA, i: numberi: number) => function (type parameter) B in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BB): function (type parameter) B in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BB
} = dual<(...args: Array<any>) => any, <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B) => B>(arity: 3, body: <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B) => B): ((...args: Array<any>) => any) & (<A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B) => B) (+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>, b: B, f: (b: B, a: A, i: number) => B): BA, function (type parameter) B in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BB>(self: Iterable<A>self: interface Iterable<T, TReturn = any, TNext = any>Iterable<function (type parameter) A in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BA>, b: Bb: function (type parameter) B in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BB, f: (b: B, a: A, i: number) => Bf: (b: Bb: function (type parameter) B in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BB, a: Aa: function (type parameter) A in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BA, i: numberi: number) => function (type parameter) B in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BB): function (type parameter) B in <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A, i: number) => B): BB =>
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).Array<A>.reduceRight<B>(callbackfn: (previousValue: B, currentValue: A, currentIndex: number, array: A[]) => B, initialValue: B): B (+2 overloads)Calls the specified callback function for all the elements in an array, in descending order. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.
reduceRight((b: Bb, a: Aa, i: numberi) => f: (b: B, a: A, i: number) => Bf(b: Bb, a: Aa, i: numberi), b: Bb)
)