NumberFromStringType-level representation of NumberFromString.
export interface NumberFromString extends interface decodeTo<To extends Constraint, From extends Constraint, RD = never, RE = never>Creates a schema that transforms from a source schema to a target schema.
When to use
Use when decoding should change the schema's decoded type or encoded shape,
with an optional custom bidirectional transformation.
Details
Call it with the target schema to and then pipe the source schema from
into the returned function. The resulting schema decodes from
From["Encoded"] to To["Type"] and encodes from To["Type"] back to
From["Encoded"].
When no transformation is provided, SchemaTransformation.passthrough() is
used, so From["Type"] must already be compatible with To["Encoded"].
The resulting schema combines decoding and encoding services from both
schemas and any custom transformation.
Gotchas
In a custom transformation, decode maps From["Type"] to To["Encoded"]
and is used on the encoding path, while encode maps To["Encoded"] to
From["Type"] and is used on the decoding path.
Example (Transforming strings to numbers with a schema transformation)
import { Schema, SchemaGetter } from "effect"
const NumberFromString = Schema.String.pipe(
Schema.decodeTo(
Schema.Number,
{
decode: SchemaGetter.transform((s) => Number(s)),
encode: SchemaGetter.transform((n) => String(n))
}
)
)
const result = Schema.decodeUnknownSync(NumberFromString)("123")
// result: 123
Type-level representation returned by
decodeTo
.
decodeTo<Finite, String> {
readonly "Rebuild": NumberFromString
}
/**
* Schema that parses a string into a `number` using JavaScript
* number coercion.
*
* **Details**
*
* Decoding:
* A `string` is decoded as a number, including possible non-finite values such as
* `NaN`, `Infinity`, and `-Infinity`. Use `FiniteFromString` to reject non-finite
* numbers.
*
* Encoding:
* A number is encoded as a `string`.
*
* @category Number
* @since 3.10.0
*/
export const const NumberFromString: NumberFromStringconst NumberFromString: {
Rebuild: NumberFromString;
Type: To["Type"];
Encoded: From["Encoded"];
DecodingServices: To["DecodingServices"] | From["DecodingServices"] | RD;
EncodingServices: To["EncodingServices"] | From["EncodingServices"] | RE;
Iso: To["Iso"];
from: From;
to: To;
ast: Ast;
annotate: (annotations: Annotations.Bottom<number, readonly []>) => NumberFromString;
annotateKey: (annotations: Annotations.Key<number>) => NumberFromString;
check: (checks_0: SchemaAST.Check<number>, ...checks: Array<SchemaAST.Check<number>>) => NumberFromString;
rebuild: (ast: SchemaAST.Number) => NumberFromString;
make: (input: number, options?: MakeOptions) => number;
makeOption: (input: number, options?: MakeOptions) => Option_.Option<number>;
makeEffect: (input: number, options?: MakeOptions) => Effect.Effect<number, SchemaError, never>;
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; <…;
}
Type-level representation of
NumberFromString
.
Schema that parses a string into a number using JavaScript
number coercion.
Details
Decoding:
A string is decoded as a number, including possible non-finite values such as
NaN, Infinity, and -Infinity. Use FiniteFromString to reject non-finite
numbers.
Encoding:
A number is encoded as a string.
NumberFromString: NumberFromString = const String: Stringconst String: {
Rebuild: Rebuild;
Iso: Iso;
ast: Ast;
Type: T;
Encoded: E;
DecodingServices: RD;
EncodingServices: RE;
annotate: (annotations: Annotations.Bottom<string, readonly []>) => String;
annotateKey: (annotations: Annotations.Key<string>) => String;
check: (checks_0: SchemaAST.Check<string>, ...checks: Array<SchemaAST.Check<string>>) => String;
rebuild: (ast: SchemaAST.String) => String;
make: (input: string, options?: MakeOptions) => string;
makeOption: (input: string, options?: MakeOptions) => Option_.Option<string>;
makeEffect: (input: string, options?: MakeOptions) => Effect.Effect<string, SchemaError, never>;
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; <…;
}
Type-level representation of
String
.
Schema for string values. Validates that the input is typeof "string".
String.Bottom<string, string, never, never, String, String, string, string, readonly [], string, "readonly", "required", "no-default", "readonly", "required">.annotate(annotations: Annotations.Bottom<string, readonly []>): Stringannotate({
Annotations.Augment.expected?: string | undefinedHuman-readable description of what a value is expected to satisfy.
Details
For filter and refinement failures, the default formatter uses
message first, then expected, and finally falls back to <filter>.
Use this to name a failed filter in the default message:
Expected <expected>, got <actual>.
expected: "a string that will be decoded as a number"
}).pipe(function decodeTo<Number, Constraint, never, never>(to: Number, transformation: {
readonly decode: SchemaGetter.Getter<number, unknown, never>;
readonly encode: SchemaGetter.Getter<unknown, number, never>;
}): (from: Constraint) => decodeTo<Number, Constraint, never, never> (+1 overload)
Creates a schema that transforms from a source schema to a target schema.
When to use
Use when decoding should change the schema's decoded type or encoded shape,
with an optional custom bidirectional transformation.
Details
Call it with the target schema to and then pipe the source schema from
into the returned function. The resulting schema decodes from
From["Encoded"] to To["Type"] and encodes from To["Type"] back to
From["Encoded"].
When no transformation is provided, SchemaTransformation.passthrough() is
used, so From["Type"] must already be compatible with To["Encoded"].
The resulting schema combines decoding and encoding services from both
schemas and any custom transformation.
Gotchas
In a custom transformation, decode maps From["Type"] to To["Encoded"]
and is used on the encoding path, while encode maps To["Encoded"] to
From["Type"] and is used on the decoding path.
Example (Transforming strings to numbers with a schema transformation)
import { Schema, SchemaGetter } from "effect"
const NumberFromString = Schema.String.pipe(
Schema.decodeTo(
Schema.Number,
{
decode: SchemaGetter.transform((s) => Number(s)),
encode: SchemaGetter.transform((n) => String(n))
}
)
)
const result = Schema.decodeUnknownSync(NumberFromString)("123")
// result: 123
decodeTo(const Number: Numberconst Number: {
Rebuild: Rebuild;
Iso: Iso;
ast: Ast;
Type: T;
Encoded: E;
DecodingServices: RD;
EncodingServices: RE;
annotate: (annotations: Annotations.Bottom<number, readonly []>) => Number;
annotateKey: (annotations: Annotations.Key<number>) => Number;
check: (checks_0: SchemaAST.Check<number>, ...checks: Array<SchemaAST.Check<number>>) => Number;
rebuild: (ast: SchemaAST.Number) => Number;
make: (input: number, options?: MakeOptions) => number;
makeOption: (input: number, options?: MakeOptions) => Option_.Option<number>;
makeEffect: (input: number, options?: MakeOptions) => Effect.Effect<number, SchemaError, never>;
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; <…;
}
Type-level representation of
Number
.
Schema for number values, including NaN, Infinity, and -Infinity.
Details
Default JSON serializer:
- Finite numbers are serialized as numbers.
- Non-finite values are serialized as strings (
"NaN", "Infinity", "-Infinity").
Number, import SchemaTransformationSchemaTransformation.const numberFromString: SchemaTransformation.Transformation<
number,
string,
never,
never
>
const numberFromString: {
_tag: 'Transformation';
decode: SchemaGetter.Getter<T, E, RD>;
encode: SchemaGetter.Getter<E, T, RE>;
flip: () => SchemaTransformation.Transformation<string, number, never, never>;
compose: (other: SchemaTransformation.Transformation<T2, number, RD2, RE2>) => SchemaTransformation.Transformation<T2, string, RD2, RE2>;
}
Decodes a string into a number and encodes a number back to a
string.
When to use
Use when you need a schema transformation to parse numeric strings from APIs,
form data, or URL parameters.
Details
Decoding coerces the string to a number like Number(s). Encoding coerces
the number to a string like String(n). This does not validate that the
result is finite; combine with Schema.Finite or Schema.Int for stricter
checks.
Example (Converting a string to a number)
import { Schema, SchemaTransformation } from "effect"
const schema = Schema.String.pipe(
Schema.decodeTo(Schema.Number, SchemaTransformation.numberFromString)
)
numberFromString))