@esfx/metadata Package

Provides an API for defining metadata about an object.

Installation

npm i @esfx/metadata

Usage

TypeScript
JavaScript (CommonJS)

import { Metadata, getObjectMetadata, getPropertyMetadata, getParameterMetadata } from "@esfx/metadata";

const Service = name => Metadata("Service", name);
const ReturnType = type => Metadata("ReturnType", type);
const Type = type => Metadata("Type", type);

@Service("MyService")
class MyClass {
    @ReturnType("string")
    method(@Type("number") x: number) {
        return "hi";
    }
}

const c = new MyClass();
getObjectMetadata(MyClass, "Service"); // "MyService"
getPropertyMetadata(c, "method", "ReturnType"); // "string"
getParameterMetadata(c, "method", 0, "Type"); // "number"

const {
    defineClassMetadata,
    defineMemberMetadata,
    defineParameterMetadata,
    getObjectMetadata,
    getPropertyMetadata,
    getParameterMetadata
} = require("@esfx/metadata");

class MyClass {
    method(x) {
        return "hi";
    }
}

defineClassMetadata(MyClass, "Service", "MyService");
defineMemberMetadata(MyClass.prototype, "method", "ReturnType", "string");
defineParameterMetadata(MyClass.prototype, "method", 0, "Type", "number");

const c = new MyClass();
getObjectMetadata(MyClass, "Service"); // "MyService"
getPropertyMetadata(c, "method", "ReturnType"); // "string"
getParameterMetadata(c, "method", 0, "Type"); // "number"

Functions

defineObjectMetadata(target, metadataKey, metadataValue)

Define metadata on an object.

Declaration

export declare function defineObjectMetadata(target: object, metadataKey: MetadataKey, metadataValue: unknown): void;

Parameters

target: object

The object.

metadataKey: MetadataKey

The metadata key.

metadataValue: unknown

The metadata value.

Returns

void

defineParameterMetadata(target, propertyKey, parameterIndex, metadataKey, metadataValue)

Define metadata on a parameter of a method of an object.

Declaration

export declare function defineParameterMetadata(target: object, propertyKey: PropertyKey, parameterIndex: number, metadataKey: MetadataKey, metadataValue: unknown): void;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the method.

parameterIndex: number

The ordinal index of the parameter.

metadataKey: MetadataKey

The metadata key.

metadataValue: unknown

The metadata value.

Returns

void

definePropertyMetadata(target, propertyKey, metadataKey, metadataValue)

Define metadata for a property of an object. The property does not have to exist.

Declaration

export declare function definePropertyMetadata(target: object, propertyKey: PropertyKey, metadataKey: MetadataKey, metadataValue: unknown): void;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the property.

metadataKey: MetadataKey

The metadata key.

metadataValue: unknown

The metadata value.

Returns

void

deleteObjectMetadata(target, metadataKey)

Deletes an own metadata key from an object.

Declaration

export declare function deleteObjectMetadata(target: object, metadataKey: MetadataKey): boolean;

Parameters

target: object

The object.

metadataKey: MetadataKey

The metadata key.

Returns

boolean

deleteParameterMetadata(target, propertyKey, parameterIndex, metadataKey)

Deletes an own metadata key from a parameter of a method of an object.

Declaration

export declare function deleteParameterMetadata(target: object, propertyKey: PropertyKey, parameterIndex: number, metadataKey: MetadataKey): boolean;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the method.

parameterIndex: number

The ordinal index of the parameter.

metadataKey: MetadataKey

The metadata key.

Returns

boolean

deletePropertyMetadata(target, propertyKey, metadataKey)

Deletes an own metadata key from a property of an object.

Declaration

export declare function deletePropertyMetadata(target: object, propertyKey: PropertyKey, metadataKey: MetadataKey): boolean;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the property.

metadataKey: MetadataKey

The metadata key.

Returns

boolean

getMetadataParameterLength(target, propertyKey)

Gets the maximum known length of a method of an object or its prototypes from its parameters that have metadata metadata.

Declaration

export declare function getMetadataParameterLength(target: object, propertyKey: PropertyKey): number;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the method.

Returns

number

getMetadataProperties(target)

Gets the property names for an object or its prototypes for which there is metadata defined.

Declaration

export declare function getMetadataProperties(target: object): (string | symbol)[];

Parameters

target: object

An object.

Returns

(string | symbol)[]

getObjectMetadata(target, metadataKey)

Gets the metadata value for a metadata key on an object or its prototypes.

Declaration

export declare function getObjectMetadata(target: object, metadataKey: MetadataKey): unknown;

Parameters

target: object

The object.

metadataKey: MetadataKey

The metadata key.

Returns

unknown

getObjectMetadataKeys(target)

Gets the metadata keys defined on an object or its prototypes.

Declaration

export declare function getObjectMetadataKeys(target: object): MetadataKey[];

Parameters

target: object

The object.

Returns

MetadataKey[]

getOwnMetadataParameterLength(target, propertyKey)

Gets the maximum known length of a method of an object from its parameters that have metadata metadata.

Declaration

export declare function getOwnMetadataParameterLength(target: object, propertyKey: PropertyKey): number;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the method.

Returns

number

getOwnMetadataProperties(target)

Gets the own property names for an object for which there is metadata defined.

Declaration

export declare function getOwnMetadataProperties(target: object): (string | symbol)[];

Parameters

target: object

An object.

Returns

(string | symbol)[]

getOwnObjectMetadata(target, metadataKey)

Gets the metadata value for an own metadata key on an object.

Declaration

export declare function getOwnObjectMetadata(target: object, metadataKey: MetadataKey): unknown;

Parameters

target: object

The object.

metadataKey: MetadataKey

The metadata key.

Returns

unknown

getOwnObjectMetadataKeys(target)

Gets the own metadata keys defined on an object.

Declaration

export declare function getOwnObjectMetadataKeys(target: object): MetadataKey[];

Parameters

target: object

The object.

Returns

MetadataKey[]

getOwnParameterMetadata(target, propertyKey, parameterIndex, metadataKey)

Gets the metadata value for an own metadata key on a parameter of a method of an object.

Declaration

export declare function getOwnParameterMetadata(target: object, propertyKey: PropertyKey, parameterIndex: number, metadataKey: MetadataKey): unknown;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the method.

parameterIndex: number

The ordinal index of the parameter.

metadataKey: MetadataKey

The metadata key.

Returns

unknown

getOwnParameterMetadataKeys(target, propertyKey, parameterIndex)

Gets the own metadata keys defined on a parameter of a method of an object.

Declaration

export declare function getOwnParameterMetadataKeys(target: object, propertyKey: PropertyKey, parameterIndex: number): MetadataKey[];

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the method.

parameterIndex: number

The ordinal index of the parameter.

Returns

MetadataKey[]

getOwnPropertyMetadata(target, propertyKey, metadataKey)

Gets the metadata value for an own metadata key on a property of an object.

Declaration

export declare function getOwnPropertyMetadata(target: object, propertyKey: PropertyKey, metadataKey: MetadataKey): unknown;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the property.

metadataKey: MetadataKey

The metadata key.

Returns

unknown

getOwnPropertyMetadataKeys(target, propertyKey)

Gets the own metadata keys defined on a property of an object.

Declaration

export declare function getOwnPropertyMetadataKeys(target: object, propertyKey: PropertyKey): MetadataKey[];

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the property.

Returns

MetadataKey[]

getParameterMetadata(target, propertyKey, parameterIndex, metadataKey)

Gets the metadata value for a metadata key on a parameter of a method of an object or its prototypes.

Declaration

export declare function getParameterMetadata(target: object, propertyKey: PropertyKey, parameterIndex: number, metadataKey: MetadataKey): unknown;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the method.

parameterIndex: number

The ordinal index of the parameter.

metadataKey: MetadataKey

The metadata key.

Returns

unknown

getParameterMetadataKeys(target, propertyKey, parameterIndex)

Gets the metadata keys defined on a parameter of a method of an object or its prototypes.

Declaration

export declare function getParameterMetadataKeys(target: object, propertyKey: PropertyKey, parameterIndex: number): MetadataKey[];

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the method.

parameterIndex: number

The ordinal index of the parameter.

Returns

MetadataKey[]

getPropertyMetadata(target, propertyKey, metadataKey)

Gets the metadata value for a metadata key on a property of an object or its prototypes.

Declaration

export declare function getPropertyMetadata(target: object, propertyKey: PropertyKey, metadataKey: MetadataKey): unknown;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the property.

metadataKey: MetadataKey

The metadata key.

Returns

unknown

getPropertyMetadataKeys(target, propertyKey)

Gets the metadata keys defined on a property of an object or its prototypes.

Declaration

export declare function getPropertyMetadataKeys(target: object, propertyKey: PropertyKey): MetadataKey[];

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the property.

Returns

MetadataKey[]

hasObjectMetadata(target, metadataKey)

Tests whether an object or its prototypes have metadata for the provided key.

Declaration

export declare function hasObjectMetadata(target: object, metadataKey: MetadataKey): boolean;

Parameters

target: object

The object.

metadataKey: MetadataKey

The metadata key.

Returns

boolean

hasOwnObjectMetadata(target, metadataKey)

Tests whether an object has own metadata for the provided key.

Declaration

export declare function hasOwnObjectMetadata(target: object, metadataKey: MetadataKey): boolean;

Parameters

target: object

The object.

metadataKey: MetadataKey

The metadata key.

Returns

boolean

hasOwnParameterMetadata(target, propertyKey, parameterIndex, metadataKey)

Tests whether a parameter of a method of an object has own metadata for the provided key.

Declaration

export declare function hasOwnParameterMetadata(target: object, propertyKey: PropertyKey, parameterIndex: number, metadataKey: MetadataKey): boolean;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the method.

parameterIndex: number

The ordinal index of the parameter.

metadataKey: MetadataKey

The metadata key.

Returns

boolean

hasOwnPropertyMetadata(target, propertyKey, metadataKey)

Tests whether a property of an object has own metadata for the provided key.

Declaration

export declare function hasOwnPropertyMetadata(target: object, propertyKey: PropertyKey, metadataKey: MetadataKey): boolean;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the property.

metadataKey: MetadataKey

The metadata key.

Returns

boolean

hasParameterMetadata(target, propertyKey, parameterIndex, metadataKey)

Tests whether a parameter of a method of an object or its prototypes have metadata for the provided key.

Declaration

export declare function hasParameterMetadata(target: object, propertyKey: PropertyKey, parameterIndex: number, metadataKey: MetadataKey): boolean;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the method.

parameterIndex: number

The ordinal index of the parameter.

metadataKey: MetadataKey

The metadata key.

Returns

boolean

hasPropertyMetadata(target, propertyKey, metadataKey)

Tests whether a property of an object or its prototypes have metadata for the provided key.

Declaration

export declare function hasPropertyMetadata(target: object, propertyKey: PropertyKey, metadataKey: MetadataKey): boolean;

Parameters

target: object

The target object.

propertyKey: PropertyKey

The name of the property.

metadataKey: MetadataKey

The metadata key.

Returns

boolean

Variables

metadata

Attaches metadata to a class, member, or parameter.

Declaration

metadata: ((metadataKey: MetadataKey, metadataValue?: unknown) => {
    (target: Function): void;
    (target: object, key: PropertyKey, descriptor?: PropertyDescriptor | undefined): void;
    (target: object, key: PropertyKey, parameterIndex: number): void;
}) & {
    defineObjectMetadata: typeof defineObjectMetadata;
    deleteObjectMetadata: typeof deleteObjectMetadata;
    hasOwnObjectMetadata: typeof hasOwnObjectMetadata;
    hasObjectMetadata: typeof hasObjectMetadata;
    getOwnObjectMetadata: typeof getOwnObjectMetadata;
    getObjectMetadata: typeof getObjectMetadata;
    getOwnObjectMetadataKeys: typeof getOwnObjectMetadataKeys;
    getObjectMetadataKeys: typeof getObjectMetadataKeys;
    definePropertyMetadata: typeof definePropertyMetadata;
    deletePropertyMetadata: typeof deletePropertyMetadata;
    hasOwnPropertyMetadata: typeof hasOwnPropertyMetadata;
    hasPropertyMetadata: typeof hasPropertyMetadata;
    getOwnPropertyMetadata: typeof getOwnPropertyMetadata;
    getPropertyMetadata: typeof getPropertyMetadata;
    getOwnPropertyMetadataKeys: typeof getOwnPropertyMetadataKeys;
    getPropertyMetadataKeys: typeof getPropertyMetadataKeys;
    getOwnMetadataProperties: typeof getOwnMetadataProperties;
    getMetadataProperties: typeof getMetadataProperties;
    defineParameterMetadata: typeof defineParameterMetadata;
    deleteParameterMetadata: typeof deleteParameterMetadata;
    hasOwnParameterMetadata: typeof hasOwnParameterMetadata;
    hasParameterMetadata: typeof hasParameterMetadata;
    getOwnParameterMetadata: typeof getOwnParameterMetadata;
    getParameterMetadata: typeof getParameterMetadata;
    getOwnParameterMetadataKeys: typeof getOwnParameterMetadataKeys;
    getParameterMetadataKeys: typeof getParameterMetadataKeys;
    getOwnMetadataParameterLength: typeof getOwnMetadataParameterLength;
    getMetadataParameterLength: typeof getMetadataParameterLength;
}

Type Aliases

MetadataKey

Declaration

export declare type MetadataKey = string | symbol | number | boolean | bigint | object;