<T, E, RD = never, RE = never>(options: {
readonly decode: (
e: E,
options: SchemaAST.ParseOptions
) => Effect.Effect<T, SchemaIssue.Issue, RD>
readonly encode: (
t: T,
options: SchemaAST.ParseOptions
) => Effect.Effect<E, SchemaIssue.Issue, RE>
}): Transformation<T, E, RD, RE>Creates a Transformation from effectful decode and encode functions that
can fail with Issue.
When to use
Use when you need a schema transformation that may fail or require Effect services.
Details
- Each function receives the input value and
ParseOptions. - Must return an
Effectthat succeeds with the output or fails withIssue. - Skips
Noneinputs (missing keys) — functions are only called on present values.
Example (Parsing a date string that can fail)
import { Effect, Option, Schema, SchemaIssue, SchemaTransformation } from "effect"
const DateFromString = Schema.String.pipe(
Schema.decodeTo(
Schema.Date,
SchemaTransformation.transformOrFail({
decode: (s) => {
const d = new Date(s)
return isNaN(d.getTime())
? Effect.fail(new SchemaIssue.InvalidValue(Option.some(s), { message: "Invalid date" }))
: Effect.succeed(d)
},
encode: (d) => Effect.succeed(d.toISOString())
})
)
)Source effect/SchemaTransformation.ts:2869 lines
export function function transformOrFail<
T,
E,
RD = never,
RE = never
>(options: {
readonly decode: (
e: E,
options: SchemaAST.ParseOptions
) => Effect.Effect<T, SchemaIssue.Issue, RD>
readonly encode: (
t: T,
options: SchemaAST.ParseOptions
) => Effect.Effect<E, SchemaIssue.Issue, RE>
}): Transformation<T, E, RD, RE>
Creates a Transformation from effectful decode and encode functions that
can fail with Issue.
When to use
Use when you need a schema transformation that may fail or require Effect
services.
Details
- Each function receives the input value and
ParseOptions.
- Must return an
Effect that succeeds with the output or fails with Issue.
- Skips
None inputs (missing keys) — functions are only called on present values.
Example (Parsing a date string that can fail)
import { Effect, Option, Schema, SchemaIssue, SchemaTransformation } from "effect"
const DateFromString = Schema.String.pipe(
Schema.decodeTo(
Schema.Date,
SchemaTransformation.transformOrFail({
decode: (s) => {
const d = new Date(s)
return isNaN(d.getTime())
? Effect.fail(new SchemaIssue.InvalidValue(Option.some(s), { message: "Invalid date" }))
: Effect.succeed(d)
},
encode: (d) => Effect.succeed(d.toISOString())
})
)
)
transformOrFail<function (type parameter) T in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
function (type parameter) E in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
function (type parameter) RD in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
function (type parameter) RE in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
options: {
readonly decode: (
e: E,
options: SchemaAST.ParseOptions
) => Effect.Effect<T, SchemaIssue.Issue, RD>
readonly encode: (
t: T,
options: SchemaAST.ParseOptions
) => Effect.Effect<E, SchemaIssue.Issue, RE>
}
decode: (
e: E,
options: SchemaAST.ParseOptions
) => Effect.Effect<T, SchemaIssue.Issue, RD>
e: Ee: function (type parameter) E in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
options: SchemaAST.ParseOptions(parameter) options: {
errors: "first" | "all" | undefined;
onExcessProperty: "ignore" | "error" | "preserve" | undefined;
propertyOrder: "none" | "original" | undefined;
disableChecks: boolean | undefined;
concurrency: number | "unbounded" | undefined;
}
import SchemaASTSchemaAST.type SchemaAST.ParseOptions = /*unresolved*/ anyParseOptions) => import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<function (type parameter) T in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
import SchemaIssueSchemaIssue.type SchemaIssue.Issue = /*unresolved*/ anyIssue, function (type parameter) RD in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
encode: (
t: T,
options: SchemaAST.ParseOptions
) => Effect.Effect<E, SchemaIssue.Issue, RE>
t: Tt: function (type parameter) T in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
options: SchemaAST.ParseOptions(parameter) options: {
errors: "first" | "all" | undefined;
onExcessProperty: "ignore" | "error" | "preserve" | undefined;
propertyOrder: "none" | "original" | undefined;
disableChecks: boolean | undefined;
concurrency: number | "unbounded" | undefined;
}
import SchemaASTSchemaAST.type SchemaAST.ParseOptions = /*unresolved*/ anyParseOptions) => import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<function (type parameter) E in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
import SchemaIssueSchemaIssue.type SchemaIssue.Issue = /*unresolved*/ anyIssue, function (type parameter) RE in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
class Transformation<in out T, in out E, RD = never, RE = never>class Transformation {
_tag: 'Transformation';
decode: SchemaGetter.Getter<T, E, RD>;
encode: SchemaGetter.Getter<E, T, RE>;
flip: () => Transformation<E, T, RE, RD>;
compose: <T2, RD2, RE2>(other: Transformation<T2, T, RD2, RE2>) => Transformation<T2, E, RD | RD2, RE | RE2>;
}
Represents a bidirectional transformation between a decoded type T and an encoded
type E, built from a pair of Getters.
When to use
Use when you need a schema transformation that defines how a schema converts
between two representations.
- You want to compose multiple transformations into a pipeline.
- You want to flip a transformation to swap decode/encode.
Details
This is the primary building block for Schema.decodeTo, Schema.encodeTo,
Schema.decode, Schema.encode, and Schema.link. Each direction is a
SchemaGetter.Getter that handles optionality, failure, and Effect services.
- Immutable —
flip() and compose() return new instances.
flip() swaps the decode and encode getters.compose(other) chains: this.decode then other.decode for decoding,
other.encode then this.encode for encoding.
Example (Composing two transformations)
import { SchemaTransformation } from "effect"
const trimAndLower = SchemaTransformation.trim().compose(
SchemaTransformation.toLowerCase()
)
// decode: trim then lowercase
// encode: passthrough (both directions)
Transformation<function (type parameter) T in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
function (type parameter) E in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
function (type parameter) RD in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
function (type parameter) RE in transformOrFail<T, E, RD = never, RE = never>(options: {
readonly decode: (e: E, options: SchemaAST.ParseOptions) => Effect.Effect<T, SchemaIssue.Issue, RD>;
readonly encode: (t: T, options: SchemaAST.ParseOptions) => Effect.Effect<E, SchemaIssue.Issue, RE>;
}): Transformation<T, E, RD, RE>
constructor Transformation<T, E, RD, RE>(decode: SchemaGetter.Getter<T, E, RD>, encode: SchemaGetter.Getter<E, T, RE>): Transformation<T, E, RD, RE>Represents a bidirectional transformation between a decoded type T and an encoded
type E, built from a pair of Getters.
When to use
Use when you need a schema transformation that defines how a schema converts
between two representations.
- You want to compose multiple transformations into a pipeline.
- You want to flip a transformation to swap decode/encode.
Details
This is the primary building block for Schema.decodeTo, Schema.encodeTo,
Schema.decode, Schema.encode, and Schema.link. Each direction is a
SchemaGetter.Getter that handles optionality, failure, and Effect services.
- Immutable —
flip() and compose() return new instances.
flip() swaps the decode and encode getters.compose(other) chains: this.decode then other.decode for decoding,
other.encode then this.encode for encoding.
Example (Composing two transformations)
import { SchemaTransformation } from "effect"
const trimAndLower = SchemaTransformation.trim().compose(
SchemaTransformation.toLowerCase()
)
// decode: trim then lowercase
// encode: passthrough (both directions)
Transformation(
import SchemaGetterSchemaGetter.transformOrFail(options: {
readonly decode: (
e: E,
options: SchemaAST.ParseOptions
) => Effect.Effect<T, SchemaIssue.Issue, RD>
readonly encode: (
t: T,
options: SchemaAST.ParseOptions
) => Effect.Effect<E, SchemaIssue.Issue, RE>
}
decode: (
e: E,
options: SchemaAST.ParseOptions
) => Effect.Effect<T, SchemaIssue.Issue, RD>
import SchemaGetterSchemaGetter.transformOrFail(options: {
readonly decode: (
e: E,
options: SchemaAST.ParseOptions
) => Effect.Effect<T, SchemaIssue.Issue, RD>
readonly encode: (
t: T,
options: SchemaAST.ParseOptions
) => Effect.Effect<E, SchemaIssue.Issue, RE>
}
encode: (
t: T,
options: SchemaAST.ParseOptions
) => Effect.Effect<E, SchemaIssue.Issue, RE>
Referenced by 11 symbols
Schema.FileSchema.FormDataSchema.RegExpSchemaTransformation.bigDecimalFromStringSchemaTransformation.dateTimeUtcFromStringSchemaTransformation.dateTimeZonedFromStringSchemaTransformation.durationFromNanosSchemaTransformation.durationFromStringSchemaTransformation.timeZoneFromStringSchemaTransformation.timeZoneNamedFromStringSchemaTransformation.urlFromString