<K extends string | symbol, B>(key: NoInfer<K>, b: B): <A>(
self: ReadonlyRecord<K, A>
) => Option.Option<Record<K, A | B>>
<K extends string | symbol, A, B>(
self: ReadonlyRecord<K, A>,
key: NoInfer<K>,
b: B
): Option.Option<Record<K, A | B>>Replaces the value at an existing key safely and returns the updated record in
Option.some.
Details
If the key is not present, returns Option.none() and leaves the record
unchanged.
Example (Replacing a value at a key)
import { Record } from "effect"
Record.replace({ a: 1, b: 2, c: 3 }, "a", 10) // Option.some({ a: 10, b: 2, c: 3 })
Record.replace(Record.empty<string>(), "a", 10) // Option.none()export const const replace: {
<K extends string | symbol, B>(
key: NoInfer<K>,
b: B
): <A>(
self: ReadonlyRecord<K, A>
) => Option.Option<Record<K, A | B>>
<K extends string | symbol, A, B>(
self: ReadonlyRecord<K, A>,
key: NoInfer<K>,
b: B
): Option.Option<Record<K, A | B>>
}
Replaces the value at an existing key safely and returns the updated record in
Option.some.
Details
If the key is not present, returns Option.none() and leaves the record
unchanged.
Example (Replacing a value at a key)
import { Record } from "effect"
Record.replace({ a: 1, b: 2, c: 3 }, "a", 10) // Option.some({ a: 10, b: 2, c: 3 })
Record.replace(Record.empty<string>(), "a", 10) // Option.none()
replace: {
<function (type parameter) K in <K extends string | symbol, B>(key: NoInfer<K>, b: B): <A>(self: ReadonlyRecord<K, A>) => Option.Option<Record<K, A | B>>K extends string | symbol, function (type parameter) B in <K extends string | symbol, B>(key: NoInfer<K>, b: B): <A>(self: ReadonlyRecord<K, A>) => Option.Option<Record<K, A | B>>B>(
key: NoInfer<K>key: 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) K in <K extends string | symbol, B>(key: NoInfer<K>, b: B): <A>(self: ReadonlyRecord<K, A>) => Option.Option<Record<K, A | B>>K>,
b: Bb: function (type parameter) B in <K extends string | symbol, B>(key: NoInfer<K>, b: B): <A>(self: ReadonlyRecord<K, A>) => Option.Option<Record<K, A | B>>B
): <function (type parameter) A in <A>(self: ReadonlyRecord<K, A>): Option.Option<Record<K, A | B>>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, B>(key: NoInfer<K>, b: B): <A>(self: ReadonlyRecord<K, A>) => Option.Option<Record<K, A | B>>K, function (type parameter) A in <A>(self: ReadonlyRecord<K, A>): Option.Option<Record<K, A | B>>A>) => import OptionOption.type Option.Option = /*unresolved*/ anyOption<type Record<K extends keyof any, T> = {
[P in K]: T
}
Construct a type with a set of properties K of type T
Record<function (type parameter) K in <K extends string | symbol, B>(key: NoInfer<K>, b: B): <A>(self: ReadonlyRecord<K, A>) => Option.Option<Record<K, A | B>>K, function (type parameter) A in <A>(self: ReadonlyRecord<K, A>): Option.Option<Record<K, A | B>>A | function (type parameter) B in <K extends string | symbol, B>(key: NoInfer<K>, b: B): <A>(self: ReadonlyRecord<K, A>) => Option.Option<Record<K, A | B>>B>>
<function (type parameter) K in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>K extends string | symbol, function (type parameter) A in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>A, function (type parameter) B in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>B>(
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, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>K, function (type parameter) A in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>A>,
key: NoInfer<K>key: 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) K in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>K>,
b: Bb: function (type parameter) B in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>B
): import OptionOption.type Option.Option = /*unresolved*/ anyOption<type Record<K extends keyof any, T> = {
[P in K]: T
}
Construct a type with a set of properties K of type T
Record<function (type parameter) K in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>K, function (type parameter) A in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>A | function (type parameter) B in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>B>>
} = import dualdual(
3,
<function (type parameter) K in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>K extends string | symbol, function (type parameter) A in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>A, function (type parameter) B in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>B>(
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, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>K, function (type parameter) A in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>A>,
key: NoInfer<K>key: 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) K in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>K>,
b: Bb: function (type parameter) B in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>B
): import OptionOption.type Option.Option = /*unresolved*/ anyOption<type Record<K extends keyof any, T> = {
[P in K]: T
}
Construct a type with a set of properties K of type T
Record<function (type parameter) K in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>K, function (type parameter) A in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>A | function (type parameter) B in <K extends string | symbol, A, B>(self: ReadonlyRecord<K, A>, key: NoInfer<K>, b: B): Option.Option<Record<K, A | B>>B>> => const modify: {
<K extends string | symbol, A, B>(
key: NoInfer<K>,
f: (a: A) => B
): (
self: ReadonlyRecord<K, A>
) => Option.Option<Record<K, A | B>>
<K extends string | symbol, A, B>(
self: ReadonlyRecord<K, A>,
key: NoInfer<K>,
f: (a: A) => B
): Option.Option<Record<K, A | B>>
}
self: ReadonlyRecord<K, A>self, key: NoInfer<K>key, () => b: Bb)
)