UndefinedType-level representation of Undefined.
export interface Undefined extends interface Bottom<out T, out E, out RD, out RE, out Ast extends SchemaAST.AST, out Rebuild extends Top, out TypeMakeIn = T, out Iso = T, in out TypeParameters extends ReadonlyArray<Constraint> = readonly [], out TypeMake = TypeMakeIn, out TypeMutability extends Mutability = "readonly", out TypeOptionality extends Optionality = "required", out TypeConstructorDefault extends ConstructorDefault = "no-default", out EncodedMutability extends Mutability = "readonly", out EncodedOptionality extends Optionality = "required">The fully-parameterized base interface for all schemas. Exposes all 14 type
parameters controlling type inference, mutability, optionality, services, and
transformation behavior.
When to use
Use when you are writing advanced generic schema utilities or performing
schema introspection.
Bottom<undefined, undefined, never, never, import SchemaASTSchemaAST.class Undefinedclass Undefined {
_tag: 'Undefined';
getParser: () => SchemaParser.Parser;
toCodecJson: () => AST;
getExpected: () => string;
annotations: Schema.Annotations.Annotations | undefined;
checks: Checks | undefined;
encoding: Encoding | undefined;
context: Context | undefined;
toString: () => string;
}
AST node matching the undefined value.
Details
Parsing succeeds only when the input is exactly undefined.
Undefined, Undefined> {}
/**
* Schema for the `undefined` literal. Validates that the input is strictly `undefined`.
*
* @see {@link UndefinedOr} for a union with another schema.
* @category schemas
* @since 3.10.0
*/
export const const Undefined: Undefinedconst Undefined: {
Rebuild: Rebuild;
Iso: Iso;
ast: Ast;
Type: T;
Encoded: E;
DecodingServices: RD;
EncodingServices: RE;
annotate: (annotations: Annotations.Bottom<undefined, readonly []>) => Undefined;
annotateKey: (annotations: Annotations.Key<undefined>) => Undefined;
check: (checks_0: SchemaAST.Check<undefined>, ...checks: Array<SchemaAST.Check<undefined>>) => Undefined;
rebuild: (ast: SchemaAST.Undefined) => Undefined;
make: (input: undefined, options?: MakeOptions) => undefined;
makeOption: (input: undefined, options?: MakeOptions) => Option_.Option<undefined>;
makeEffect: (input: undefined, options?: MakeOptions) => Effect.Effect<undefined, 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
Undefined
.
Schema for the undefined literal. Validates that the input is strictly undefined.
Undefined: Undefined = const make: <S extends Constraint>(
ast: S["ast"],
options?: object
) => S
Creates a schema from an AST (Abstract Syntax Tree) node.
Details
This is the fundamental constructor for all schemas in the Effect Schema
library. It takes an AST node and wraps it in a fully-typed schema that
preserves all type information and provides the complete schema API.
The make function is used internally to create all primitive schemas like
String, Number, Boolean, etc., as well as more complex schemas. It's
the bridge between the untyped AST representation and the strongly-typed
schema.
make(import SchemaASTSchemaAST.const undefined: SchemaAST.Undefined(alias) const undefined: {
_tag: 'Undefined';
getParser: () => SchemaParser.Parser;
toCodecJson: () => AST;
getExpected: () => string;
annotations: Schema.Annotations.Annotations | undefined;
checks: Checks | undefined;
encoding: Encoding | undefined;
context: Context | undefined;
toString: () => string;
}
Provides the singleton
Undefined
AST instance.
When to use
Use when you need the shared AST node for exact undefined values while
inspecting or constructing schema ASTs.
undefined)