MappedType

Package: @opra/common

MappedType is the runtime class that represents a derived object type created by applying field transformations to an existing ComplexType, MixinType, or another MappedType. It is the runtime counterpart of the OmitType, PickType, PartialType, and RequiredType factory functions.

A MappedType shares the full field API of ComplexTypeBase — you can iterate its fields, look up individual fields, and generate codecs, just like with ComplexType.

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Inheritance

DocumentElement
└── DataType
    └── ComplexTypeBase      ← shared field API (fields, findField, getField, …)
        └── MappedType

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Properties

Properties inherited from DataType:

Property	Type	Description
kind	'MappedType'	Always 'MappedType'.
name	string | undefined	Registry name. undefined for anonymous mapped types.
description	string | undefined	Human-readable description.
abstract	boolean | undefined	Whether the type is abstract.
embedded	boolean	true when the type has no name.

Properties inherited from ComplexTypeBase:

Property	Type	Description
keyField	string | undefined	Primary key field name (inherited from base if the key field was not omitted).
additionalFields	boolean | DataType | ['error'] | ['error', string] | undefined	Inherited from base (suppressed when pick is set).
ctor	Type | undefined	TypeScript class constructor (inherited from base).

Properties on MappedType:

Property	Type	Description
base	ComplexType | MappedType | MixinType	The source type this MappedType was derived from.
pick	string[] | undefined	Field names retained from base (set when created via PickType).
omit	string[] | undefined	Field names removed from base (set when created via OmitType).
partial	string[] | boolean | undefined	Fields made optional — array of names, or true for all (set via PartialType).
required	string[] | boolean | undefined	Fields made required — array of names, or true for all (set via RequiredType).
discriminatorField	string | undefined	Inherited from base.
discriminatorValue	string | undefined	Inherited from base.

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Field methods

All field methods are inherited from ComplexTypeBase and behave identically to ComplexType. See ComplexType — Field methods.

Method	Description
findField(nameOrPath, scope?)	Returns the ApiField at the given name/path, or undefined.
getField(nameOrPath, scope?)	Same as findField but throws if not found.
fields(scope?)	Iterator over all ApiField instances visible in scope.
fieldNames(scope?)	Iterator over field names.
fieldEntries(scope?)	Iterator over [name, ApiField] pairs.
fieldCount(scope?)	Count of fields visible in scope.
parseFieldPath(path, options?)	Resolves a dot-separated path to an array of ParsedFieldPath items.
normalizeFieldPath(path, options?)	Resolves a path and returns its canonical dot-separated form.

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Methods

extendsFrom(baseType)

Returns true if this mapped type's base (or its base chain) extends from the given type.

extendsFrom(baseType: DataType | string | Type | object): boolean

const updateDto = document.node.getDataType('UpdateCustomerDto');
if (updateDto instanceof MappedType) {
  updateDto.extendsFrom('Customer'); // true if derived from Customer
}

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generateCodec(codec, options?)

Inherited from ComplexTypeBase. Compiles a codec that validates/transforms the fields of this mapped type (respecting pick/omit and partial/required transformations).

generateCodec(
  codec: 'encode' | 'decode',
  options?: DataType.GenerateCodecOptions
): Validator

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toJSON(options?)

Returns an OpraSchema.MappedType plain object for schema export, including base, pick/omit, and partial/required.

toJSON(options?: ApiDocument.ExportOptions): OpraSchema.MappedType

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Obtaining a MappedType instance

Mapped types appear in a document when a controller or operation registers a type produced by OmitType, PickType, PartialType, or RequiredType.

import { MappedType } from '@opra/common';

const type = document.node.getDataType('UpdateCustomerDto');

if (type instanceof MappedType) {
  console.log(type.kind);           // 'MappedType'
  console.log(type.base.name);      // 'Customer'
  console.log(type.omit);           // ['_id'] or undefined
  console.log(type.partial);        // true or string[]
}

→ ApiDocument · MappedType · ComplexType