Transformation<URL, string, never, never>Decodes a string into a URL and encodes a URL back to its href
string.
When to use
Use when you need a schema transformation to parse URL strings from user input or API responses.
Details
Decoding checks URL.canParse(s) and fails with InvalidValue if the string
is not a valid URL. Encoding returns url.href.
Example (Converting a string to a URL)
import { Schema, SchemaTransformation } from "effect"
const schema = Schema.String.pipe(
Schema.decodeTo(Schema.URL, SchemaTransformation.urlFromString)
)export const const urlFromString: Transformation<
URL,
string
>
const urlFromString: {
_tag: 'Transformation';
decode: SchemaGetter.Getter<T, E, RD>;
encode: SchemaGetter.Getter<E, T, RE>;
flip: () => Transformation<string, URL, never, never>;
compose: (other: Transformation<T2, URL, RD2, RE2>) => Transformation<T2, string, RD2, RE2>;
}
Decodes a string into a URL and encodes a URL back to its href
string.
When to use
Use when you need a schema transformation to parse URL strings from user
input or API responses.
Details
Decoding checks URL.canParse(s) and fails with InvalidValue if the string
is not a valid URL. Encoding returns url.href.
Example (Converting a string to a URL)
import { Schema, SchemaTransformation } from "effect"
const schema = Schema.String.pipe(
Schema.decodeTo(Schema.URL, SchemaTransformation.urlFromString)
)
urlFromString: 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<URL, string> = 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<URL, string>({
decode: (
e: string,
options: SchemaAST.ParseOptions
) => Effect.Effect<URL, SchemaIssue.Issue, never>
s: strings) =>
var URL: {
new (
url: string | URL,
base?: string | URL
): URL
prototype: URL
canParse(
url: string | URL,
base?: string | URL
): boolean
createObjectURL(obj: Blob | MediaSource): string
parse(
url: string | URL,
base?: string | URL
): URL | null
revokeObjectURL(url: string): void
}
The URL interface is used to parse, construct, normalize, and encode URL.
URL.function canParse(url: string | URL, base?: string | URL): booleanThe URL.canParse() static method of the URL interface returns a boolean indicating whether or not an absolute URL, or a relative URL combined with a base URL, are parsable and valid.
canParse(s: strings)
? import EffectEffect.succeed(new var URL: new (
url: string | URL,
base?: string | URL
) => URL
The URL interface is used to parse, construct, normalize, and encode URL.
URL(s: strings))
: import EffectEffect.fail(new import SchemaIssueSchemaIssue.InvalidValue(import OptionOption.some(s: strings), { message: stringmessage: `Invalid URL string: ${s: strings}` })),
encode: (
t: URL,
options: SchemaAST.ParseOptions
) => Effect.Effect<
string,
SchemaIssue.Issue,
never
>
url: URLurl) => import EffectEffect.succeed(url: URLurl.URL.href: stringThe href property of the URL interface is a string containing the whole URL.
href)
})