<A, B>(i: number, f: (a: A) => B): (
self: Chunk<A>
) => O.Option<Chunk<A | B>>
<A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>Applies a function to the element at the specified index safely, creating a new Chunk,
or returns None if the index is out of bounds.
Example (Modifying an element)
import { Chunk } from "effect"
const chunk = Chunk.make(1, 2, 3, 4)
const result = Chunk.modify(chunk, 1, (n) => n * 10)
console.log(result) // Option.some(Chunk.make(1, 20, 3, 4))
// Index out of bounds returns None
const outOfBounds = chunk.pipe(Chunk.modify(10, (n) => n * 10))
console.log(outOfBounds) // Option.none()
// Negative index returns None
const negative = chunk.pipe(Chunk.modify(-1, (n) => n * 10))
console.log(negative) // Option.none()export const const modify: {
<A, B>(i: number, f: (a: A) => B): (
self: Chunk<A>
) => O.Option<Chunk<A | B>>
<A, B>(
self: Chunk<A>,
i: number,
f: (a: A) => B
): O.Option<Chunk<A | B>>
}
Applies a function to the element at the specified index safely, creating a new Chunk,
or returns None if the index is out of bounds.
Example (Modifying an element)
import { Chunk } from "effect"
const chunk = Chunk.make(1, 2, 3, 4)
const result = Chunk.modify(chunk, 1, (n) => n * 10)
console.log(result) // Option.some(Chunk.make(1, 20, 3, 4))
// Index out of bounds returns None
const outOfBounds = chunk.pipe(Chunk.modify(10, (n) => n * 10))
console.log(outOfBounds) // Option.none()
// Negative index returns None
const negative = chunk.pipe(Chunk.modify(-1, (n) => n * 10))
console.log(negative) // Option.none()
modify: {
<function (type parameter) A in <A, B>(i: number, f: (a: A) => B): (self: Chunk<A>) => O.Option<Chunk<A | B>>A, function (type parameter) B in <A, B>(i: number, f: (a: A) => B): (self: Chunk<A>) => O.Option<Chunk<A | B>>B>(i: numberi: number, f: (a: A) => Bf: (a: Aa: function (type parameter) A in <A, B>(i: number, f: (a: A) => B): (self: Chunk<A>) => O.Option<Chunk<A | B>>A) => function (type parameter) B in <A, B>(i: number, f: (a: A) => B): (self: Chunk<A>) => O.Option<Chunk<A | B>>B): (self: Chunk<A>(parameter) self: {
length: number;
right: Chunk<A>;
left: Chunk<A>;
backing: Backing<A>;
depth: number;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Chunk<out A>A Chunk is an immutable, ordered collection optimized for efficient concatenation and access patterns.
Example (Inspecting chunk values)
import { Chunk } from "effect"
const chunk: Chunk.Chunk<number> = Chunk.make(1, 2, 3)
console.log(chunk.length) // 3
console.log(Chunk.toArray(chunk)) // [1, 2, 3]
A namespace containing utility types for Chunk operations.
Example (Working with Chunk utility types)
import type { Chunk } from "effect"
// Extract the element type from a Chunk
declare const chunk: Chunk.Chunk<string>
type ElementType = Chunk.Chunk.Infer<typeof chunk> // string
// Create a preserving non-emptiness
declare const nonEmptyChunk: Chunk.NonEmptyChunk<number>
type WithString = Chunk.Chunk.With<typeof nonEmptyChunk, string> // Chunk.NonEmptyChunk<string>
Chunk<function (type parameter) A in <A, B>(i: number, f: (a: A) => B): (self: Chunk<A>) => O.Option<Chunk<A | B>>A>) => import OO.type Option<A> = O.None<A> | O.Some<A>The Option data type represents optional values. An Option<A> is either
Some<A>, containing a value of type A, or None, representing absence.
When to use
Use to represent initial values that may not yet exist
- Returning from partial functions (not defined for all inputs)
- Managing optional fields in data structures
Namespace containing utility types for Option.
When to use
Use to access type-level helpers associated with Option.
Option<interface Chunk<out A>A Chunk is an immutable, ordered collection optimized for efficient concatenation and access patterns.
Example (Inspecting chunk values)
import { Chunk } from "effect"
const chunk: Chunk.Chunk<number> = Chunk.make(1, 2, 3)
console.log(chunk.length) // 3
console.log(Chunk.toArray(chunk)) // [1, 2, 3]
A namespace containing utility types for Chunk operations.
Example (Working with Chunk utility types)
import type { Chunk } from "effect"
// Extract the element type from a Chunk
declare const chunk: Chunk.Chunk<string>
type ElementType = Chunk.Chunk.Infer<typeof chunk> // string
// Create a preserving non-emptiness
declare const nonEmptyChunk: Chunk.NonEmptyChunk<number>
type WithString = Chunk.Chunk.With<typeof nonEmptyChunk, string> // Chunk.NonEmptyChunk<string>
Chunk<function (type parameter) A in <A, B>(i: number, f: (a: A) => B): (self: Chunk<A>) => O.Option<Chunk<A | B>>A | function (type parameter) B in <A, B>(i: number, f: (a: A) => B): (self: Chunk<A>) => O.Option<Chunk<A | B>>B>>
<function (type parameter) A in <A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>A, function (type parameter) B in <A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>B>(self: Chunk<A>(parameter) self: {
length: number;
right: Chunk<A>;
left: Chunk<A>;
backing: Backing<A>;
depth: number;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Chunk<out A>A Chunk is an immutable, ordered collection optimized for efficient concatenation and access patterns.
Example (Inspecting chunk values)
import { Chunk } from "effect"
const chunk: Chunk.Chunk<number> = Chunk.make(1, 2, 3)
console.log(chunk.length) // 3
console.log(Chunk.toArray(chunk)) // [1, 2, 3]
A namespace containing utility types for Chunk operations.
Example (Working with Chunk utility types)
import type { Chunk } from "effect"
// Extract the element type from a Chunk
declare const chunk: Chunk.Chunk<string>
type ElementType = Chunk.Chunk.Infer<typeof chunk> // string
// Create a preserving non-emptiness
declare const nonEmptyChunk: Chunk.NonEmptyChunk<number>
type WithString = Chunk.Chunk.With<typeof nonEmptyChunk, string> // Chunk.NonEmptyChunk<string>
Chunk<function (type parameter) A in <A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>A>, i: numberi: number, f: (a: A) => Bf: (a: Aa: function (type parameter) A in <A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>A) => function (type parameter) B in <A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>B): import OO.type Option<A> = O.None<A> | O.Some<A>The Option data type represents optional values. An Option<A> is either
Some<A>, containing a value of type A, or None, representing absence.
When to use
Use to represent initial values that may not yet exist
- Returning from partial functions (not defined for all inputs)
- Managing optional fields in data structures
Namespace containing utility types for Option.
When to use
Use to access type-level helpers associated with Option.
Option<interface Chunk<out A>A Chunk is an immutable, ordered collection optimized for efficient concatenation and access patterns.
Example (Inspecting chunk values)
import { Chunk } from "effect"
const chunk: Chunk.Chunk<number> = Chunk.make(1, 2, 3)
console.log(chunk.length) // 3
console.log(Chunk.toArray(chunk)) // [1, 2, 3]
A namespace containing utility types for Chunk operations.
Example (Working with Chunk utility types)
import type { Chunk } from "effect"
// Extract the element type from a Chunk
declare const chunk: Chunk.Chunk<string>
type ElementType = Chunk.Chunk.Infer<typeof chunk> // string
// Create a preserving non-emptiness
declare const nonEmptyChunk: Chunk.NonEmptyChunk<number>
type WithString = Chunk.Chunk.With<typeof nonEmptyChunk, string> // Chunk.NonEmptyChunk<string>
Chunk<function (type parameter) A in <A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>A | function (type parameter) B in <A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>B>>
} = dual<(...args: Array<any>) => any, <A, B>(self: Chunk<A>, i: number, f: (a: A) => B) => O.Option<Chunk<A | B>>>(arity: 3, body: <A, B>(self: Chunk<A>, i: number, f: (a: A) => B) => O.Option<Chunk<A | B>>): ((...args: Array<any>) => any) & (<A, B>(self: Chunk<A>, i: number, f: (a: A) => B) => O.Option<Chunk<A | 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: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>A, function (type parameter) B in <A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>B>(self: Chunk<A>(parameter) self: {
length: number;
right: Chunk<A>;
left: Chunk<A>;
backing: Backing<A>;
depth: number;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Chunk<out A>A Chunk is an immutable, ordered collection optimized for efficient concatenation and access patterns.
Example (Inspecting chunk values)
import { Chunk } from "effect"
const chunk: Chunk.Chunk<number> = Chunk.make(1, 2, 3)
console.log(chunk.length) // 3
console.log(Chunk.toArray(chunk)) // [1, 2, 3]
A namespace containing utility types for Chunk operations.
Example (Working with Chunk utility types)
import type { Chunk } from "effect"
// Extract the element type from a Chunk
declare const chunk: Chunk.Chunk<string>
type ElementType = Chunk.Chunk.Infer<typeof chunk> // string
// Create a preserving non-emptiness
declare const nonEmptyChunk: Chunk.NonEmptyChunk<number>
type WithString = Chunk.Chunk.With<typeof nonEmptyChunk, string> // Chunk.NonEmptyChunk<string>
Chunk<function (type parameter) A in <A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>A>, i: numberi: number, f: (a: A) => Bf: (a: Aa: function (type parameter) A in <A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>A) => function (type parameter) B in <A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>B): import OO.type Option<A> = O.None<A> | O.Some<A>The Option data type represents optional values. An Option<A> is either
Some<A>, containing a value of type A, or None, representing absence.
When to use
Use to represent initial values that may not yet exist
- Returning from partial functions (not defined for all inputs)
- Managing optional fields in data structures
Namespace containing utility types for Option.
When to use
Use to access type-level helpers associated with Option.
Option<interface Chunk<out A>A Chunk is an immutable, ordered collection optimized for efficient concatenation and access patterns.
Example (Inspecting chunk values)
import { Chunk } from "effect"
const chunk: Chunk.Chunk<number> = Chunk.make(1, 2, 3)
console.log(chunk.length) // 3
console.log(Chunk.toArray(chunk)) // [1, 2, 3]
A namespace containing utility types for Chunk operations.
Example (Working with Chunk utility types)
import type { Chunk } from "effect"
// Extract the element type from a Chunk
declare const chunk: Chunk.Chunk<string>
type ElementType = Chunk.Chunk.Infer<typeof chunk> // string
// Create a preserving non-emptiness
declare const nonEmptyChunk: Chunk.NonEmptyChunk<number>
type WithString = Chunk.Chunk.With<typeof nonEmptyChunk, string> // Chunk.NonEmptyChunk<string>
Chunk<function (type parameter) A in <A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>A | function (type parameter) B in <A, B>(self: Chunk<A>, i: number, f: (a: A) => B): O.Option<Chunk<A | B>>B>> =>
pipe<Option<unknown>, Option<Chunk<A | B>>>(a: Option<unknown>, ab: (a: Option<unknown>) => Option<Chunk<A | B>>): Option<Chunk<A | B>> (+19 overloads)Pipes the value of an expression through a left-to-right sequence of
functions.
When to use
Use when you need to compose data-last functions into readable
transformation pipelines instead of method-style chains.
Details
Takes an initial value, passes it to the first function, then passes each
result to the next function in order. The final function result is returned.
Gotchas
Each function passed after the initial value must accept a single argument,
because pipe calls each step with only the previous result.
Example (Piping values through functions)
In this example, 1 is passed to the first function, and each result becomes
the input for the next function.
import { pipe } from "effect"
const result = pipe(
1,
(n) => n + 1,
(n) => n * 2,
(n) => `result: ${n}`
)
console.log(result) // "result: 4"
Example (Chaining methods before conversion)
const numbers = [1, 2, 3, 4]
const double = (n: number) => n * 2
const greaterThanFour = (n: number) => n > 4
const result = numbers.map(double).filter(greaterThanFour)
console.log(result) // [6, 8]
Example (Rewriting method chains with pipe)
The same transformation can be written with data-last functions.
import { Array, pipe } from "effect"
const numbers = [1, 2, 3, 4]
const double = (n: number) => n * 2
const greaterThanFour = (n: number) => n > 4
const result = pipe(
numbers,
Array.map(double),
Array.filter(greaterThanFour)
)
console.log(result) // [6, 8]
Example (Chaining arithmetic operations)
import { pipe } from "effect"
// Define simple arithmetic operations
const increment = (x: number) => x + 1
const double = (x: number) => x * 2
const subtractTen = (x: number) => x - 10
// Sequentially apply these operations using `pipe`
const result = pipe(5, increment, double, subtractTen)
console.log(result)
// Output: 2
Example (Building a simple transformation pipeline)
import { pipe } from "effect"
// Simple transformation pipeline
const result = pipe(
5,
(x) => x * 2, // 10
(x) => x + 1, // 11
(x) => x.toString() // "11"
)
console.log(result) // "11"
pipe(import RARA.modify(const toReadonlyArray: <
S extends Chunk<any>
>(
self: S
) => S extends NonEmptyChunk<any>
? RA.NonEmptyReadonlyArray<Chunk.Infer<S>>
: ReadonlyArray<Chunk.Infer<S>>
Converts a Chunk into a ReadonlyArray. If the provided Chunk is
non-empty (NonEmptyChunk), the function will return a
NonEmptyReadonlyArray, ensuring the non-empty property is preserved.
Example (Converting chunks to readonly arrays)
import { Chunk } from "effect"
const chunk = Chunk.make(1, 2, 3)
const readonlyArray = Chunk.toReadonlyArray(chunk)
console.log(readonlyArray) // [1, 2, 3]
// The result is read-only, modifications would cause TypeScript errors
// readonlyArray[0] = 10 // TypeScript error
// With empty chunk
const emptyChunk = Chunk.empty<number>()
console.log(Chunk.toReadonlyArray(emptyChunk)) // []
toReadonlyArray(self: Chunk<A>(parameter) self: {
length: number;
right: Chunk<A>;
left: Chunk<A>;
backing: Backing<A>;
depth: number;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
i: numberi, f: (a: A) => Bf), import OO.const map: {
<A, B>(f: (a: A) => B): (
self: Option<A>
) => Option<B>
<A, B>(
self: Option<A>,
f: (a: A) => B
): Option<B>
}
const fromArrayUnsafe: <A>(
self: ReadonlyArray<A>
) => Chunk<A>
Wraps an array into a chunk without copying.
When to use
Use when the input array can be shared with the resulting Chunk and avoiding
a copy matters.
Gotchas
Mutating the source array after wrapping can mutate the resulting Chunk.
Example (Creating chunks without copying arrays)
import { Chunk } from "effect"
const array = [1, 2, 3, 4, 5]
const chunk = Chunk.fromArrayUnsafe(array)
console.log(Chunk.toArray(chunk)) // [1, 2, 3, 4, 5]
// Warning: Since this doesn't copy the array, mutations affect the chunk
array[0] = 999
console.log(Chunk.toArray(chunk)) // [999, 2, 3, 4, 5]
fromArrayUnsafe))
)