Function.flow — API

Function.flowfunctioneffect/Function.ts:1162

<A extends ReadonlyArray<unknown>, B = never>(ab: (...a: A) => B): (
  ...a: A
) => B
<A extends ReadonlyArray<unknown>, B = never, C = never>(
  ab: (...a: A) => B,
  bc: (b: B) => C
): (...a: A) => C
<A extends ReadonlyArray<unknown>, B = never, C = never, D = never>(
  ab: (...a: A) => B,
  bc: (b: B) => C,
  cd: (c: C) => D
): (...a: A) => D
<
  A extends ReadonlyArray<unknown>,
  B = never,
  C = never,
  D = never,
  E = never
>(
  ab: (...a: A) => B,
  bc: (b: B) => C,
  cd: (c: C) => D,
  de: (d: D) => E
): (...a: A) => E
<
  A extends ReadonlyArray<unknown>,
  B = never,
  C = never,
  D = never,
  E = never,
  F = never
>(
  ab: (...a: A) => B,
  bc: (b: B) => C,
  cd: (c: C) => D,
  de: (d: D) => E,
  ef: (e: E) => F
): (...a: A) => F
<
  A extends ReadonlyArray<unknown>,
  B = never,
  C = never,
  D = never,
  E = never,
  F = never,
  G = never
>(
  ab: (...a: A) => B,
  bc: (b: B) => C,
  cd: (c: C) => D,
  de: (d: D) => E,
  ef: (e: E) => F,
  fg: (f: F) => G
): (...a: A) => G
<
  A extends ReadonlyArray<unknown>,
  B = never,
  C = never,
  D = never,
  E = never,
  F = never,
  G = never,
  H = never
>(
  ab: (...a: A) => B,
  bc: (b: B) => C,
  cd: (c: C) => D,
  de: (d: D) => E,
  ef: (e: E) => F,
  fg: (f: F) => G,
  gh: (g: G) => H
): (...a: A) => H
<
  A extends ReadonlyArray<unknown>,
  B = never,
  C = never,
  D = never,
  E = never,
  F = never,
  G = never,
  H = never,
  I = never
>(
  ab: (...a: A) => B,
  bc: (b: B) => C,
  cd: (c: C) => D,
  de: (d: D) => E,
  ef: (e: E) => F,
  fg: (f: F) => G,
  gh: (g: G) => H,
  hi: (h: H) => I
): (...a: A) => I
<
  A extends ReadonlyArray<unknown>,
  B = never,
  C = never,
  D = never,
  E = never,
  F = never,
  G = never,
  H = never,
  I = never,
  J = never
>(
  ab: (...a: A) => B,
  bc: (b: B) => C,
  cd: (c: C) => D,
  de: (d: D) => E,
  ef: (e: E) => F,
  fg: (f: F) => G,
  gh: (g: G) => H,
  hi: (h: H) => I,
  ij: (i: I) => J
): (...a: A) => J

Performs left-to-right function composition.

When to use

Use to build a reusable function from a left-to-right sequence of transformations.

Details

The first function may have any arity. Every following function must be unary.

Example (Composing functions left to right)

import { flow } from "effect"
import * as assert from "node:assert"

const len = (s: string): number => s.length
const double = (n: number): number => n * 2

const f = flow(len, double)

assert.strictEqual(f("aaa"), 6)

combinatorspipe compose

Source effect/Function.ts:1162164 lines

export function flow<A extends ReadonlyArray<unknown>, B = never>(
  ab: (...a: A) => B
): (...a: A) => B
export function flow<A extends ReadonlyArray<unknown>, B = never, C = never>(
  ab: (...a: A) => B,
  bc: (b: B) => C
): (...a: A) => C
export function flow<
  A extends ReadonlyArray<unknown>,
  B = never,
  C = never,
  D = never
>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D): (...a: A) => D
export function flow<
  A extends ReadonlyArray<unknown>,
  B = never,
  C = never,
  D = never,
  E = never
>(
  ab: (...a: A) => B,
  bc: (b: B) => C,
  cd: (c: C) => D,
  de: (d: D) => E
): (...a: A) => E
export function flow<
  A extends ReadonlyArray<unknown>,
  B = never,
  C = never,
  D = never,
  E = never,
  F = never
>(
  ab: (...a: A) => B,
  bc: (b: B) => C,
  cd: (c: C) => D,
  de: (d: D) => E,
  ef: (e: E) => F
): (...a: A) => F
export function flow<
  A extends ReadonlyArray<unknown>,
  B = never,
  C = never,
  D = never,
  E = never,
  F = never,
  G = never
>(
  ab: (...a: A) => B,
  bc: (b: B) => C,
  cd: (c: C) => D,
  de: (d: D) => E,
  ef: (e: E) => F,
  fg: (f: F) => G
): (...a: A) => G
export function flow<
  A extends ReadonlyArray<unknown>,
  B = never,
  C = never,
  D = never,
  E = never,
  F = never,
  G = never,
  H = never
>(
  ab: (...a: A) => B,
  bc: (b: B) => C,
  cd: (c: C) => D,
  de: (d: D) => E,
  ef: (e: E) => F,
  fg: (f: F) => G,
  gh: (g: G) => H
): (...a: A) => H
export function flow<
  A extends ReadonlyArray<unknown>,
  B = never,
  C = never,
  D = never,
  E = never,
  F = never,
  G = never,
  H = never,
  I = never
>(
  ab: (...a: A) => B,
  bc: (b: B) => C,
  cd: (c: C) => D,
  de: (d: D) => E,
  ef: (e: E) => F,
  fg: (f: F) => G,
  gh: (g: G) => H,
  hi: (h: H) => I
): (...a: A) => I
export function flow<
  A extends ReadonlyArray<unknown>,
  B = never,
  C = never,
  D = never,
  E = never,
  F = never,
  G = never,
  H = never,
  I = never,
  J = never
>(
  ab: (...a: A) => B,
  bc: (b: B) => C,
  cd: (c: C) => D,
  de: (d: D) => E,
  ef: (e: E) => F,
  fg: (f: F) => G,
  gh: (g: G) => H,
  hi: (h: H) => I,
  ij: (i: I) => J
): (...a: A) => J
export function flow(
  ab: Function,
  bc?: Function,
  cd?: Function,
  de?: Function,
  ef?: Function,
  fg?: Function,
  gh?: Function,
  hi?: Function,
  ij?: Function
): unknown {
  switch (arguments.length) {
    case 1:
      return ab
    case 2:
      return function(this: unknown) {
        return bc!(ab.apply(this, arguments))
      }
    case 3:
      return function(this: unknown) {
        return cd!(bc!(ab.apply(this, arguments)))
      }
    case 4:
      return function(this: unknown) {
        return de!(cd!(bc!(ab.apply(this, arguments))))
      }
    case 5:
      return function(this: unknown) {
        return ef!(de!(cd!(bc!(ab.apply(this, arguments)))))
      }
    case 6:
      return function(this: unknown) {
        return fg!(ef!(de!(cd!(bc!(ab.apply(this, arguments))))))
      }
    case 7:
      return function(this: unknown) {
        return gh!(fg!(ef!(de!(cd!(bc!(ab.apply(this, arguments)))))))
      }
    case 8:
      return function(this: unknown) {
        return hi!(gh!(fg!(ef!(de!(cd!(bc!(ab.apply(this, arguments))))))))
      }
    case 9:
      return function(this: unknown) {
        return ij!(hi!(gh!(fg!(ef!(de!(cd!(bc!(ab.apply(this, arguments)))))))))
      }
  }
  return
}

Referenced by 7 symbols

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