<K extends string | symbol, X extends K>(key: X): <A>(
self: ReadonlyRecord<K, A>
) => Record<Exclude<K, X>, A>
<K extends string | symbol, A, X extends K>(
self: ReadonlyRecord<K, A>,
key: X
): Record<Exclude<K, X>, A>Removes a key from a record.
When to use
Use to create a shallow copy of a record without one property.
Details
If the key is not present, the result is still a shallow copy of the original record.
Example (Removing a key)
import { Record } from "effect"
import * as assert from "node:assert"
assert.deepStrictEqual(Record.remove({ a: 1, b: 2 }, "a"), { b: 2 })export const const remove: {
<K extends string | symbol, X extends K>(
key: X
): <A>(
self: ReadonlyRecord<K, A>
) => Record<Exclude<K, X>, A>
<K extends string | symbol, A, X extends K>(
self: ReadonlyRecord<K, A>,
key: X
): Record<Exclude<K, X>, A>
}
Removes a key from a record.
When to use
Use to create a shallow copy of a record without one property.
Details
If the key is not present, the result is still a shallow copy of the original
record.
Example (Removing a key)
import { Record } from "effect"
import * as assert from "node:assert"
assert.deepStrictEqual(Record.remove({ a: 1, b: 2 }, "a"), { b: 2 })
remove: {
<function (type parameter) K in <K extends string | symbol, X extends K>(key: X): <A>(self: ReadonlyRecord<K, A>) => Record<Exclude<K, X>, A>K extends string | symbol, function (type parameter) X in <K extends string | symbol, X extends K>(key: X): <A>(self: ReadonlyRecord<K, A>) => Record<Exclude<K, X>, A>X extends function (type parameter) K in <K extends string | symbol, X extends K>(key: X): <A>(self: ReadonlyRecord<K, A>) => Record<Exclude<K, X>, A>K>(key: X extends Kkey: function (type parameter) X in <K extends string | symbol, X extends K>(key: X): <A>(self: ReadonlyRecord<K, A>) => Record<Exclude<K, X>, A>X): <function (type parameter) A in <A>(self: ReadonlyRecord<K, A>): Record<Exclude<K, X>, A>A>(self: ReadonlyRecord<K, A>self: type ReadonlyRecord<in out K extends string | symbol, out A> = { readonly [P in K]: A; }Represents a readonly record with keys of type K and values of type A.
This is the foundational type for immutable key-value mappings in Effect.
Example (Defining a readonly record type)
import type { Record } from "effect"
// Creating a readonly record type
type UserRecord = Record.ReadonlyRecord<"name" | "age", string | number>
const user: UserRecord = {
name: "John",
age: 30
}
Namespace containing utility types for working with readonly records.
These types help with type-level operations on record keys and values.
Example (Using readonly record helper types)
import type { Record } from "effect"
// Using NonLiteralKey to convert literal keys to generic types
type GenericKey = Record.ReadonlyRecord.NonLiteralKey<"foo" | "bar"> // string
// Using IntersectKeys to find common keys between record types
type CommonKeys = Record.ReadonlyRecord.IntersectKeys<"a" | "b", "b" | "c"> // "b"
ReadonlyRecord<function (type parameter) K in <K extends string | symbol, X extends K>(key: X): <A>(self: ReadonlyRecord<K, A>) => Record<Exclude<K, X>, A>K, function (type parameter) A in <A>(self: ReadonlyRecord<K, A>): Record<Exclude<K, X>, A>A>) => type Record<K extends keyof any, T> = {
[P in K]: T
}
Construct a type with a set of properties K of type T
Record<type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) K in <K extends string | symbol, X extends K>(key: X): <A>(self: ReadonlyRecord<K, A>) => Record<Exclude<K, X>, A>K, function (type parameter) X in <K extends string | symbol, X extends K>(key: X): <A>(self: ReadonlyRecord<K, A>) => Record<Exclude<K, X>, A>X>, function (type parameter) A in <A>(self: ReadonlyRecord<K, A>): Record<Exclude<K, X>, A>A>
<function (type parameter) K in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>K extends string | symbol, function (type parameter) A in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>A, function (type parameter) X in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>X extends function (type parameter) K in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>K>(self: ReadonlyRecord<K, A>self: type ReadonlyRecord<in out K extends string | symbol, out A> = { readonly [P in K]: A; }Represents a readonly record with keys of type K and values of type A.
This is the foundational type for immutable key-value mappings in Effect.
Example (Defining a readonly record type)
import type { Record } from "effect"
// Creating a readonly record type
type UserRecord = Record.ReadonlyRecord<"name" | "age", string | number>
const user: UserRecord = {
name: "John",
age: 30
}
Namespace containing utility types for working with readonly records.
These types help with type-level operations on record keys and values.
Example (Using readonly record helper types)
import type { Record } from "effect"
// Using NonLiteralKey to convert literal keys to generic types
type GenericKey = Record.ReadonlyRecord.NonLiteralKey<"foo" | "bar"> // string
// Using IntersectKeys to find common keys between record types
type CommonKeys = Record.ReadonlyRecord.IntersectKeys<"a" | "b", "b" | "c"> // "b"
ReadonlyRecord<function (type parameter) K in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>K, function (type parameter) A in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>A>, key: X extends Kkey: function (type parameter) X in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>X): type Record<K extends keyof any, T> = {
[P in K]: T
}
Construct a type with a set of properties K of type T
Record<type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) K in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>K, function (type parameter) X in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>X>, function (type parameter) A in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>A>
} = dual<(...args: Array<any>) => any, <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X) => Record<Exclude<K, X>, A>>(arity: 2, body: <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X) => Record<Exclude<K, X>, A>): ((...args: Array<any>) => any) & (<K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X) => Record<Exclude<K, X>, 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) K in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>K extends string | symbol, function (type parameter) A in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>A, function (type parameter) X in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>X extends function (type parameter) K in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>K>(self: ReadonlyRecord<K, A>self: type ReadonlyRecord<in out K extends string | symbol, out A> = { readonly [P in K]: A; }Represents a readonly record with keys of type K and values of type A.
This is the foundational type for immutable key-value mappings in Effect.
Example (Defining a readonly record type)
import type { Record } from "effect"
// Creating a readonly record type
type UserRecord = Record.ReadonlyRecord<"name" | "age", string | number>
const user: UserRecord = {
name: "John",
age: 30
}
Namespace containing utility types for working with readonly records.
These types help with type-level operations on record keys and values.
Example (Using readonly record helper types)
import type { Record } from "effect"
// Using NonLiteralKey to convert literal keys to generic types
type GenericKey = Record.ReadonlyRecord.NonLiteralKey<"foo" | "bar"> // string
// Using IntersectKeys to find common keys between record types
type CommonKeys = Record.ReadonlyRecord.IntersectKeys<"a" | "b", "b" | "c"> // "b"
ReadonlyRecord<function (type parameter) K in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>K, function (type parameter) A in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>A>, key: X extends Kkey: function (type parameter) X in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>X): type Record<K extends keyof any, T> = {
[P in K]: T
}
Construct a type with a set of properties K of type T
Record<type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) K in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>K, function (type parameter) X in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>X>, function (type parameter) A in <K extends string | symbol, A, X extends K>(self: ReadonlyRecord<K, A>, key: X): Record<Exclude<K, X>, A>A> => {
if (!const has: {
<K extends string | symbol>(key: NoInfer<K>): <
A
>(
self: ReadonlyRecord<K, A>
) => boolean
<K extends string | symbol, A>(
self: ReadonlyRecord<K, A>,
key: NoInfer<K>
): boolean
}
self: ReadonlyRecord<K, A>self, key: X extends Kkey)) {
return { ...self: ReadonlyRecord<K, A>self }
}
const const out: ReadonlyRecord<K, A>out = { ...self: ReadonlyRecord<K, A>self }
delete const out: ReadonlyRecord<K, A>out[key: X extends Kkey]
return const out: ReadonlyRecord<K, A>out
}
)