BaseRepresents the abstract base class for all AST node variants.
Details
Every AST node extends Base and inherits these fields:
annotations— user-supplied metadata (identifier, title, description, arbitrary keys).checks— optional Checks for post-type-match validation.encoding— optional Encoding chain for type ↔ wire transformations.context— optional Context for per-property metadata.
Subclasses add a _tag discriminant and variant-specific data.
export abstract class class Baseclass Base {
_tag: string;
annotations: Schema.Annotations.Annotations | undefined;
checks: Checks | undefined;
encoding: Encoding | undefined;
context: Context | undefined;
toString: () => string;
}
Represents the abstract base class for all
AST
node variants.
Details
Every AST node extends Base and inherits these fields:
annotations — user-supplied metadata (identifier, title, description,
arbitrary keys).checks — optional
Checks
for post-type-match validation.encoding — optional
Encoding
chain for type ↔ wire
transformations.context — optional
Context
for per-property metadata.
Subclasses add a _tag discriminant and variant-specific data.
Base {
readonly [const TypeId: "~effect/Schema"TypeId] = const TypeId: "~effect/Schema"TypeId
abstract readonly Base._tag: string_tag: string
readonly Base.annotations: Schema.Annotations.Annotations | undefinedannotations: import SchemaSchema.Annotations.interface Annotations.AnnotationsThis interface is used to define the annotations that can be attached to a
schema. You can extend this interface to define your own annotations.
Details
Note that both a missing key or undefined is used to indicate that the
annotation is not present.
This means that can remove any annotation by setting it to undefined.
Example (Defining your own annotations)
import { Schema } from "effect"
// Extend the Annotations interface with a custom `version` annotation
declare module "effect/Schema" {
namespace Annotations {
interface Annotations {
readonly version?:
| readonly [major: number, minor: number, patch: number]
| undefined
}
}
}
// The `version` annotation is now recognized by the TypeScript compiler
const schema = Schema.String.annotate({ version: [1, 2, 0] })
// const version: readonly [major: number, minor: number, patch: number] | undefined
const version = Schema.resolveAnnotations(schema)?.["version"]
if (version) {
// Access individual parts of the version
console.log(version[1])
// Output: 2
}
Annotations | undefined
readonly Base.checks: Checks | undefinedchecks: type Checks = readonly [
Check<any>,
...Check<any>[]
]
Non-empty array of validation
Check
values attached to an AST node
via
Base.checks
.
Details
Checks are run after basic type matching succeeds. They represent
refinements like minLength, pattern, int, etc.
Checks | undefined
readonly Base.encoding: Encoding | undefinedencoding: type Encoding = readonly [Link, ...Link[]]A non-empty chain of
Link
values representing the transformation
steps between a schema's decoded (type) form and its encoded (wire) form.
Details
Stored on
Base.encoding
. When undefined, the node has no
encoding transformation (type and encoded forms are identical).
Encoding | undefined
readonly Base.context: Context | undefinedcontext: class Contextclass Context {
isOptional: boolean;
isMutable: boolean;
defaultValue: Encoding | undefined;
annotations: Schema.Annotations.Key<unknown> | undefined;
}
Represents per-property metadata attached to AST nodes via
Base.context
.
Details
Tracks whether a property key is optional, mutable, has a constructor
default, or carries key-level annotations. Typically set by helpers like
optionalKey
and Schema.mutableKey.
isOptional — the property key may be absent from the input.isMutable — the property is readonly when false.defaultValue — an
Encoding
applied during construction to
supply missing values.annotations — key-level annotations (e.g. description of the key
itself).
Context | undefined
constructor(
annotations: | Schema.Annotations.Annotations
| undefined
import SchemaSchema.Annotations.interface Annotations.AnnotationsThis interface is used to define the annotations that can be attached to a
schema. You can extend this interface to define your own annotations.
Details
Note that both a missing key or undefined is used to indicate that the
annotation is not present.
This means that can remove any annotation by setting it to undefined.
Example (Defining your own annotations)
import { Schema } from "effect"
// Extend the Annotations interface with a custom `version` annotation
declare module "effect/Schema" {
namespace Annotations {
interface Annotations {
readonly version?:
| readonly [major: number, minor: number, patch: number]
| undefined
}
}
}
// The `version` annotation is now recognized by the TypeScript compiler
const schema = Schema.String.annotate({ version: [1, 2, 0] })
// const version: readonly [major: number, minor: number, patch: number] | undefined
const version = Schema.resolveAnnotations(schema)?.["version"]
if (version) {
// Access individual parts of the version
console.log(version[1])
// Output: 2
}
Annotations | undefined = var undefinedundefined,
checks: Checks | undefinedchecks: type Checks = readonly [
Check<any>,
...Check<any>[]
]
Non-empty array of validation
Check
values attached to an AST node
via
Base.checks
.
Details
Checks are run after basic type matching succeeds. They represent
refinements like minLength, pattern, int, etc.
Checks | undefined = var undefinedundefined,
encoding: Encoding | undefinedencoding: type Encoding = readonly [Link, ...Link[]]A non-empty chain of
Link
values representing the transformation
steps between a schema's decoded (type) form and its encoded (wire) form.
Details
Stored on
Base.encoding
. When undefined, the node has no
encoding transformation (type and encoded forms are identical).
Encoding | undefined = var undefinedundefined,
context: Context | undefinedcontext: class Contextclass Context {
isOptional: boolean;
isMutable: boolean;
defaultValue: Encoding | undefined;
annotations: Schema.Annotations.Key<unknown> | undefined;
}
Represents per-property metadata attached to AST nodes via
Base.context
.
Details
Tracks whether a property key is optional, mutable, has a constructor
default, or carries key-level annotations. Typically set by helpers like
optionalKey
and Schema.mutableKey.
isOptional — the property key may be absent from the input.isMutable — the property is readonly when false.defaultValue — an
Encoding
applied during construction to
supply missing values.annotations — key-level annotations (e.g. description of the key
itself).
Context | undefined = var undefinedundefined
) {
this.Base.annotations: Schema.Annotations.Annotations | undefinedannotations = annotations: | Schema.Annotations.Annotations
| undefined
Base.checks: Checks | undefinedchecks = checks: Checks | undefinedchecks
this.Base.encoding: Encoding | undefinedencoding = encoding: Encoding | undefinedencoding
this.Base.context: Context | undefinedcontext = context: Context | undefinedcontext
}
Base.toString(): stringtoString() {
return `<${this.Base._tag: string_tag}>`
}
}