flow

Defined in: Composition/flow.ts:45

Properties

async

readonly async: {<A, B>(ab): (a) => Promise<B>; <A, B, C>(ab, bc): (a) => Promise<C>; <A, B, C, D>(ab, bc, cd): (a) => Promise<D>; <A, B, C, D, E>(ab, bc, cd, de): (a) => Promise<E>; <A, B, C, D, E, F>(ab, bc, cd, de, ef): (a) => Promise<F>; <A, B, C, D, E, F, G>(ab, bc, cd, de, ef, fg): (a) => Promise<G>; <A, B, C, D, E, F, G, H>(ab, bc, cd, de, ef, fg, gh): (a) => Promise<H>; <A, B, C, D, E, F, G, H, I>(ab, bc, cd, de, ef, fg, gh, hi): (a) => Promise<I>; <A, B, C, D, E, F, G, H, I, J>(ab, bc, cd, de, ef, fg, gh, hi, ij): (a) => Promise<J>; <A, B, C, D, E, F, G, H, I, J, K>(ab, bc, cd, de, ef, fg, gh, hi, ij, jk): (a) => Promise<K>; }

Defined in: Composition/flow.ts:477

Pipes a value through a sequence of operations, supporting asynchronous transitions at any step.

Call Signature

<A, B>(ab): (a) => Promise<B>

Type Parameters

A

A

B

B

Parameters

ab

(a) => Awaitable<B>

Returns

(a) => Promise<B>

Call Signature

<A, B, C>(ab, bc): (a) => Promise<C>

Type Parameters

A

A

B

B

C

C

Parameters

ab

(a) => Awaitable<B>

bc

(b) => Awaitable<C>

Returns

(a) => Promise<C>

Call Signature

<A, B, C, D>(ab, bc, cd): (a) => Promise<D>

Type Parameters

A

A

B

B

C

C

D

D

Parameters

ab

(a) => Awaitable<B>

bc

(b) => Awaitable<C>

cd

(c) => Awaitable<D>

Returns

(a) => Promise<D>

Call Signature

<A, B, C, D, E>(ab, bc, cd, de): (a) => Promise<E>

Type Parameters

A

A

B

B

C

C

D

D

E

E

Parameters

ab

(a) => Awaitable<B>

bc

(b) => Awaitable<C>

cd

(c) => Awaitable<D>

de

(d) => Awaitable<E>

Returns

(a) => Promise<E>

Call Signature

<A, B, C, D, E, F>(ab, bc, cd, de, ef): (a) => Promise<F>

Type Parameters

A

A

B

B

C

C

D

D

E

E

F

F

Parameters

ab

(a) => Awaitable<B>

bc

(b) => Awaitable<C>

cd

(c) => Awaitable<D>

de

(d) => Awaitable<E>

ef

(e) => Awaitable<F>

Returns

(a) => Promise<F>

Call Signature

<A, B, C, D, E, F, G>(ab, bc, cd, de, ef, fg): (a) => Promise<G>

Type Parameters

A

A

B

B

C

C

D

D

E

E

F

F

G

G

Parameters

ab

(a) => Awaitable<B>

bc

(b) => Awaitable<C>

cd

(c) => Awaitable<D>

de

(d) => Awaitable<E>

ef

(e) => Awaitable<F>

fg

(f) => Awaitable<G>

Returns

(a) => Promise<G>

Call Signature

<A, B, C, D, E, F, G, H>(ab, bc, cd, de, ef, fg, gh): (a) => Promise<H>

Type Parameters

A

A

B

B

C

C

D

D

E

E

F

F

G

G

H

H

Parameters

ab

(a) => Awaitable<B>

bc

(b) => Awaitable<C>

cd

(c) => Awaitable<D>

de

(d) => Awaitable<E>

ef

(e) => Awaitable<F>

fg

(f) => Awaitable<G>

gh

(g) => Awaitable<H>

Returns

(a) => Promise<H>

Call Signature

<A, B, C, D, E, F, G, H, I>(ab, bc, cd, de, ef, fg, gh, hi): (a) => Promise<I>

Type Parameters

A

A

B

B

C

C

D

D

E

E

F

F

G

G

H

H

I

I

Parameters

ab

(a) => Awaitable<B>

bc

(b) => Awaitable<C>

cd

(c) => Awaitable<D>

de

(d) => Awaitable<E>

ef

(e) => Awaitable<F>

fg

(f) => Awaitable<G>

gh

(g) => Awaitable<H>

hi

(h) => Awaitable<I>

Returns

(a) => Promise<I>

Call Signature

<A, B, C, D, E, F, G, H, I, J>(ab, bc, cd, de, ef, fg, gh, hi, ij): (a) => Promise<J>

Type Parameters

A

A

B

B

C

C

D

D

E

E

F

F

G

G

H

H

I

I

J

J

Parameters

ab

(a) => Awaitable<B>

bc

(b) => Awaitable<C>

cd

(c) => Awaitable<D>

de

(d) => Awaitable<E>

ef

(e) => Awaitable<F>

fg

(f) => Awaitable<G>

gh

(g) => Awaitable<H>

hi

(h) => Awaitable<I>

ij

(i) => J

Returns

(a) => Promise<J>

Call Signature

<A, B, C, D, E, F, G, H, I, J, K>(ab, bc, cd, de, ef, fg, gh, hi, ij, jk): (a) => Promise<K>

Type Parameters

A

A

B

B

C

C

D

D

E

E

F

F

G

G

H

H

I

I

J

J

K

K

Parameters

ab

(a) => Awaitable<B>

bc

(b) => Awaitable<C>

cd

(c) => Awaitable<D>

de

(d) => Awaitable<E>

ef

(e) => Awaitable<F>

fg

(f) => Awaitable<G>

gh

(g) => Awaitable<H>

hi

(h) => Awaitable<I>

ij

(i) => Awaitable<J>

jk

(j) => Awaitable<K>

Returns

(a) => Promise<K>

Example

const processId = flow.async(
  (id: number) => Promise.resolve(`user-${id}`),
  name => name.toUpperCase()
);
await processId(42); // "USER-42"

---

either

readonly either: <A, B>(predicate, onTrue, onFalse) => (a) => B

Defined in: Composition/flow.ts:416

Executes one of two functions based on a predicate, acting as a functional if-else/ternary helper.

Type Parameters

A

A

B

B

Parameters

predicate

(a) => boolean

onTrue

(a) => B

onFalse

(a) => B

Returns

(a) => B

Example

const formatNumber = flow.either(
  (n: number) => n >= 0,
  n => `+${n}`,
  n => `${n}`
);
formatNumber(5);  // "+5"
formatNumber(-3); // "-3"

---

safe

readonly safe: {<A, B>(ab): (a) => B | Extract<A, null | undefined>; <A, B, C>(ab, bc): (a) => C | Extract<A, null | undefined> | Extract<B, null | undefined>; <A, B, C, D>(ab, bc, cd): (a) => D | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined>; <A, B, C, D, E>(ab, bc, cd, de): (a) => E | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined>; <A, B, C, D, E, F>(ab, bc, cd, de, ef): (a) => F | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined>; <A, B, C, D, E, F, G>(ab, bc, cd, de, ef, fg): (a) => G | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined>; <A, B, C, D, E, F, G, H>(ab, bc, cd, de, ef, fg, gh): (a) => H | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined> | Extract<G, null | undefined>; <A, B, C, D, E, F, G, H, I>(ab, bc, cd, de, ef, fg, gh, hi): (a) => I | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined> | Extract<G, null | undefined> | Extract<H, null | undefined>; <A, B, C, D, E, F, G, H, I, J>(ab, bc, cd, de, ef, fg, gh, hi, ij): (a) => J | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined> | Extract<G, null | undefined> | Extract<H, null | undefined> | Extract<I, null | undefined>; <A, B, C, D, E, F, G, H, I, J, K>(ab, bc, cd, de, ef, fg, gh, hi, ij, jk): (a) => K | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined> | Extract<G, null | undefined> | Extract<H, null | undefined> | Extract<I, null | undefined> | Extract<J, null | undefined>; }

Defined in: Composition/flow.ts:463

Pipes a value through a sequence of operations, short-circuiting and propagating null or undefined immediately if any intermediate step evaluates to nil.

Call Signature

<A, B>(ab): (a) => B | Extract<A, null | undefined>

Type Parameters

A

A

B

B

Parameters

ab

(a) => B

Returns

(a) => B | Extract<A, null | undefined>

Call Signature

<A, B, C>(ab, bc): (a) => C | Extract<A, null | undefined> | Extract<B, null | undefined>

Type Parameters

A

A

B

B

C

C

Parameters

ab

(a) => B

bc

(b) => C

Returns

(a) => C | Extract<A, null | undefined> | Extract<B, null | undefined>

Call Signature

<A, B, C, D>(ab, bc, cd): (a) => D | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined>

Type Parameters

A

A

B

B

C

C

D

D

Parameters

ab

(a) => B

bc

(b) => C

cd

(c) => D

Returns

(a) => D | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined>

Call Signature

<A, B, C, D, E>(ab, bc, cd, de): (a) => E | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined>

Type Parameters

A

A

B

B

C

C

D

D

E

E

Parameters

ab

(a) => B

bc

(b) => C

cd

(c) => D

de

(d) => E

Returns

(a) => E | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined>

Call Signature

<A, B, C, D, E, F>(ab, bc, cd, de, ef): (a) => F | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined>

Type Parameters

A

A

B

B

C

C

D

D

E

E

F

F

Parameters

ab

(a) => B

bc

(b) => C

cd

(c) => D

de

(d) => E

ef

(e) => F

Returns

(a) => F | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined>

Call Signature

<A, B, C, D, E, F, G>(ab, bc, cd, de, ef, fg): (a) => G | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined>

Type Parameters

A

A

B

B

C

C

D

D

E

E

F

F

G

G

Parameters

ab

(a) => B

bc

(b) => C

cd

(c) => D

de

(d) => E

ef

(e) => F

fg

(f) => G

Returns

(a) => G | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined>

Call Signature

<A, B, C, D, E, F, G, H>(ab, bc, cd, de, ef, fg, gh): (a) => H | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined> | Extract<G, null | undefined>

Type Parameters

A

A

B

B

C

C

D

D

E

E

F

F

G

G

H

H

Parameters

ab

(a) => B

bc

(b) => C

cd

(c) => D

de

(d) => E

ef

(e) => F

fg

(f) => G

gh

(g) => H

Returns

(a) => H | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined> | Extract<G, null | undefined>

Call Signature

<A, B, C, D, E, F, G, H, I>(ab, bc, cd, de, ef, fg, gh, hi): (a) => I | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined> | Extract<G, null | undefined> | Extract<H, null | undefined>

Type Parameters

A

A

B

B

C

C

D

D

E

E

F

F

G

G

H

H

I

I

Parameters

ab

(a) => B

bc

(b) => C

cd

(c) => D

de

(d) => E

ef

(e) => F

fg

(f) => G

gh

(g) => H

hi

(h) => I

Returns

(a) => I | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined> | Extract<G, null | undefined> | Extract<H, null | undefined>

Call Signature

<A, B, C, D, E, F, G, H, I, J>(ab, bc, cd, de, ef, fg, gh, hi, ij): (a) => J | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined> | Extract<G, null | undefined> | Extract<H, null | undefined> | Extract<I, null | undefined>

Type Parameters

A

A

B

B

C

C

D

D

E

E

F

F

G

G

H

H

I

I

J

J

Parameters

ab

(a) => B

bc

(b) => C

cd

(c) => D

de

(d) => E

ef

(e) => F

fg

(f) => G

gh

(g) => H

hi

(h) => I

ij

(i) => J

Returns

(a) => J | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined> | Extract<G, null | undefined> | Extract<H, null | undefined> | Extract<I, null | undefined>

Call Signature

<A, B, C, D, E, F, G, H, I, J, K>(ab, bc, cd, de, ef, fg, gh, hi, ij, jk): (a) => K | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined> | Extract<G, null | undefined> | Extract<H, null | undefined> | Extract<I, null | undefined> | Extract<J, null | undefined>

Type Parameters

A

A

B

B

C

C

D

D

E

E

F

F

G

G

H

H

I

I

J

J

K

K

Parameters

ab

(a) => B

bc

(b) => C

cd

(c) => D

de

(d) => E

ef

(e) => F

fg

(f) => G

gh

(g) => H

hi

(h) => I

ij

(i) => J

jk

(j) => K

Returns

(a) => K | Extract<A, null | undefined> | Extract<B, null | undefined> | Extract<C, null | undefined> | Extract<D, null | undefined> | Extract<E, null | undefined> | Extract<F, null | undefined> | Extract<G, null | undefined> | Extract<H, null | undefined> | Extract<I, null | undefined> | Extract<J, null | undefined>

Example

const getCityLength = flow.safe(
  (user: { address?: { city?: string } }) => user.address,
  address => address.city,
  city => city.length
);
getCityLength({ address: { city: "Paris" } }); // 5
getCityLength({});                            // undefined

---

struct

readonly struct: <A, R>(fields) => (a) => R

Defined in: Composition/flow.ts:446

Builds an object by applying a record of field-level transformer functions to the piped input.

Type Parameters

A

A

R

R extends Record<string, unknown>

Parameters

fields

{ [K in string | number | symbol]: (a: A) => R[K] }

Returns

(a) => R

Example

type User = { name: string; age: number };
const summarizeUser = flow.struct<User, { name: string; isAdult: boolean }>({
  name: u => u.name,
  isAdult: u => u.age >= 18,
});
summarizeUser({ name: "Alice", age: 25 }); // { name: "Alice", isAdult: true }

---

try

readonly try: <A, B, C>(f, onError) => (a) => B | C

Defined in: Composition/flow.ts:431

Creates a pipeline step that wraps a throwing function in a try/catch, returning a fallback value if an error occurs.

Type Parameters

A

A

B

B

C

C

Parameters

f

(a) => B

onError

(error, value) => C

Returns

(a) => B | C

Example

const safeParse = flow.try(
  (s: string) => JSON.parse(s),
  (_err, _s) => null
);
safeParse('{"a":1}'); // { a: 1 }
safeParse('invalid'); // null

---

unless

readonly unless: <A>(predicate, onFalse) => (a) => A

Defined in: Composition/flow.ts:400

Executes a function on the piped value if a predicate is NOT met, otherwise returns the value unchanged.

Type Parameters

A

A

Parameters

predicate

(a) => boolean

onFalse

(a) => A

Returns

(a) => A

Example

const doubleIfOdd = flow.unless(
  (n: number) => n % 2 === 0,
  n => n * 2
);
doubleIfOdd(5); // 10
doubleIfOdd(4); // 4

---

when

readonly when: <A>(predicate, onTrue) => (a) => A

Defined in: Composition/flow.ts:385

Executes a function on the piped value if a predicate is met, otherwise returns the value unchanged.

Type Parameters

A

A

Parameters

predicate

(a) => boolean

onTrue

(a) => A

Returns

(a) => A

Example

const doubleIfEven = flow.when(
  (n: number) => n % 2 === 0,
  n => n * 2
);
doubleIfEven(4); // 8
doubleIfEven(5); // 5