<const T, E>(t: T): Getter<T, E>Creates a getter that always produces the given constant value, ignoring the input.
When to use
Use when you need a schema getter that always decodes a field to a fixed value.
Details
The getter is pure and always returns Option.some(t) regardless of whether
the input is Some or None.
Example (Returning a constant getter)
import { SchemaGetter } from "effect"
const alwaysZero = SchemaGetter.succeed(0)
// alwaysZero: Getter<0, unknown> — always produces 0export function function succeed<T, E>(t: T): Getter<T, E>Creates a getter that always produces the given constant value, ignoring the input.
When to use
Use when you need a schema getter that always decodes a field to a fixed
value.
Details
The getter is pure and always returns Option.some(t) regardless of whether
the input is Some or None.
Example (Returning a constant getter)
import { SchemaGetter } from "effect"
const alwaysZero = SchemaGetter.succeed(0)
// alwaysZero: Getter<0, unknown> — always produces 0
succeed<const function (type parameter) T in succeed<const T, E>(t: T): Getter<T, E>T, function (type parameter) E in succeed<const T, E>(t: T): Getter<T, E>E>(t: const Tt: function (type parameter) T in succeed<const T, E>(t: T): Getter<T, E>T): class Getter<out T, in E, R = never>class Getter {
run: (input: Option.Option<E>, options: SchemaAST.ParseOptions) => Effect.Effect<Option.Option<T>, SchemaIssue.Issue, R>;
map: <T2>(f: (t: T) => T2) => Getter<T2, E, R>;
compose: <T2, R2>(other: Getter<T2, T, R2>) => Getter<T2, E, R | R2>;
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; <…;
}
Represents a composable transformation from an encoded type E to a decoded type T.
When to use
Use when you need a schema getter to build and compose custom transformations
for Schema.decodeTo or Schema.decode.
Details
A getter wraps a function Option<E> -> Effect<Option<T>, Issue, R>. It
receives Option.None when the encoded key is absent, such as a missing
struct field, and returns Option.None to omit the value from the decoded
output. It fails with Issue on invalid input and may require Effect
services via R. .map(f) applies f to the decoded value inside Some
while leaving None unchanged. .compose(other) chains two getters by
feeding the output of this into other; passthrough getters on either side
are optimized away.
Example (Creating and composing getters)
import { SchemaGetter } from "effect"
const parseNumber = SchemaGetter.transform<number, string>((s) => Number(s))
const double = SchemaGetter.transform<number, number>((n) => n * 2)
const composed = parseNumber.compose(double)
// composed: Getter<number, string> — parses then doubles
Getter<function (type parameter) T in succeed<const T, E>(t: T): Getter<T, E>T, function (type parameter) E in succeed<const T, E>(t: T): Getter<T, E>E> {
return new constructor Getter<T, E, never>(run: (input: Option.Option<E>, options: SchemaAST.ParseOptions) => Effect.Effect<Option.Option<T>, SchemaIssue.Issue, never>): Getter<T, E, never>Represents a composable transformation from an encoded type E to a decoded type T.
When to use
Use when you need a schema getter to build and compose custom transformations
for Schema.decodeTo or Schema.decode.
Details
A getter wraps a function Option<E> -> Effect<Option<T>, Issue, R>. It
receives Option.None when the encoded key is absent, such as a missing
struct field, and returns Option.None to omit the value from the decoded
output. It fails with Issue on invalid input and may require Effect
services via R. .map(f) applies f to the decoded value inside Some
while leaving None unchanged. .compose(other) chains two getters by
feeding the output of this into other; passthrough getters on either side
are optimized away.
Example (Creating and composing getters)
import { SchemaGetter } from "effect"
const parseNumber = SchemaGetter.transform<number, string>((s) => Number(s))
const double = SchemaGetter.transform<number, number>((n) => n * 2)
const composed = parseNumber.compose(double)
// composed: Getter<number, string> — parses then doubles
Getter(() => import EffectEffect.succeedSome(t: const Tt))
}