<A>(predicate: Predicate<NoInfer<A>>): (self: Chunk<A>) => Chunk<A>
<A>(self: Chunk<A>, predicate: Predicate<A>): Chunk<A>Drops all elements so long as the predicate returns true.
Example (Dropping elements while a predicate matches)
import { Chunk } from "effect"
const chunk = Chunk.make(1, 2, 3, 4, 5)
const result = Chunk.dropWhile(chunk, (n) => n < 3)
console.log(Chunk.toArray(result)) // [3, 4, 5]export const const dropWhile: {
<A>(predicate: Predicate<NoInfer<A>>): (
self: Chunk<A>
) => Chunk<A>
<A>(
self: Chunk<A>,
predicate: Predicate<A>
): Chunk<A>
}
Drops all elements so long as the predicate returns true.
Example (Dropping elements while a predicate matches)
import { Chunk } from "effect"
const chunk = Chunk.make(1, 2, 3, 4, 5)
const result = Chunk.dropWhile(chunk, (n) => n < 3)
console.log(Chunk.toArray(result)) // [3, 4, 5]
dropWhile: {
<function (type parameter) A in <A>(predicate: Predicate<NoInfer<A>>): (self: Chunk<A>) => Chunk<A>A>(predicate: Predicate<NoInfer<A>>predicate: interface Predicate<in A>A function that decides whether a value of type A satisfies a condition.
When to use
Use when you want a reusable boolean check for A, especially when you plan
to combine checks with
and
/
or
or pass a predicate to arrays
and iterables.
Details
A predicate returns true or false and never throws by itself. It does not
narrow types unless you use Refinement.
Example (Defining a predicate)
import { Predicate } from "effect"
const isPositive: Predicate.Predicate<number> = (n) => n > 0
console.log(isPositive(1))
Type-level utilities for working with
Predicate
types.
When to use
Use when you need to extract input types from predicate signatures while
writing generic helpers over predicate types.
Details
These utilities are type-only, create no runtime values, and the namespace is
erased at runtime.
Example (Extracting predicate input)
import { Predicate } from "effect"
type IsString = Predicate.Predicate<string>
type Input = Predicate.Predicate.In<IsString>
Predicate<type NoInfer<A> = [A][A extends any ? 0 : never]Prevents TypeScript from inferring a type parameter from a specific
position.
When to use
Use when a function parameter must match an inferred type without becoming
an inference source.
Details
The parameter using NoInfer must still match the inferred type.
Example (Controlling inference)
import type { Types } from "effect"
declare function withDefault<T>(value: T, fallback: Types.NoInfer<T>): T
// T is inferred as "a" | "b" from the first argument only
const result = withDefault<"a" | "b">("a", "b")
NoInfer<function (type parameter) A in <A>(predicate: Predicate<NoInfer<A>>): (self: Chunk<A>) => Chunk<A>A>>): (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>(predicate: Predicate<NoInfer<A>>): (self: Chunk<A>) => Chunk<A>A>) => 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>(predicate: Predicate<NoInfer<A>>): (self: Chunk<A>) => Chunk<A>A>
<function (type parameter) A in <A>(self: Chunk<A>, predicate: Predicate<A>): Chunk<A>A>(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>(self: Chunk<A>, predicate: Predicate<A>): Chunk<A>A>, predicate: Predicate<A>predicate: interface Predicate<in A>A function that decides whether a value of type A satisfies a condition.
When to use
Use when you want a reusable boolean check for A, especially when you plan
to combine checks with
and
/
or
or pass a predicate to arrays
and iterables.
Details
A predicate returns true or false and never throws by itself. It does not
narrow types unless you use Refinement.
Example (Defining a predicate)
import { Predicate } from "effect"
const isPositive: Predicate.Predicate<number> = (n) => n > 0
console.log(isPositive(1))
Type-level utilities for working with
Predicate
types.
When to use
Use when you need to extract input types from predicate signatures while
writing generic helpers over predicate types.
Details
These utilities are type-only, create no runtime values, and the namespace is
erased at runtime.
Example (Extracting predicate input)
import { Predicate } from "effect"
type IsString = Predicate.Predicate<string>
type Input = Predicate.Predicate.In<IsString>
Predicate<function (type parameter) A in <A>(self: Chunk<A>, predicate: Predicate<A>): Chunk<A>A>): 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>(self: Chunk<A>, predicate: Predicate<A>): Chunk<A>A>
} = dual<(...args: Array<any>) => any, <A>(self: Chunk<A>, predicate: Predicate<A>) => Chunk<A>>(arity: 2, body: <A>(self: Chunk<A>, predicate: Predicate<A>) => Chunk<A>): ((...args: Array<any>) => any) & (<A>(self: Chunk<A>, predicate: Predicate<A>) => Chunk<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(2, <function (type parameter) A in <A>(self: Chunk<A>, predicate: Predicate<A>): Chunk<A>A>(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>(self: Chunk<A>, predicate: Predicate<A>): Chunk<A>A>, predicate: Predicate<A>predicate: interface Predicate<in A>A function that decides whether a value of type A satisfies a condition.
When to use
Use when you want a reusable boolean check for A, especially when you plan
to combine checks with
and
/
or
or pass a predicate to arrays
and iterables.
Details
A predicate returns true or false and never throws by itself. It does not
narrow types unless you use Refinement.
Example (Defining a predicate)
import { Predicate } from "effect"
const isPositive: Predicate.Predicate<number> = (n) => n > 0
console.log(isPositive(1))
Type-level utilities for working with
Predicate
types.
When to use
Use when you need to extract input types from predicate signatures while
writing generic helpers over predicate types.
Details
These utilities are type-only, create no runtime values, and the namespace is
erased at runtime.
Example (Extracting predicate input)
import { Predicate } from "effect"
type IsString = Predicate.Predicate<string>
type Input = Predicate.Predicate.In<IsString>
Predicate<function (type parameter) A in <A>(self: Chunk<A>, predicate: Predicate<A>): Chunk<A>A>): 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>(self: Chunk<A>, predicate: Predicate<A>): Chunk<A>A> => {
const const arr: readonly A[]arr = 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;
}
const len: numberlen = const arr: readonly A[]arr.ReadonlyArray<T>.length: numberGets the length of the array. This is a number one higher than the highest element defined in an array.
length
let let i: numberi = 0
while (let i: numberi < const len: numberlen && predicate: Predicate<A>predicate(const arr: readonly A[]arr[let i: numberi]!)) {
let i: numberi++
}
return const drop: {
(n: number): <A>(self: Chunk<A>) => Chunk<A>
<A>(self: Chunk<A>, n: number): Chunk<A>
}
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;
}
let i: numberi)
})