ReflectNoConflict.ts

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// Metadata Proposal
// https://rbuckton.github.io/reflect-metadata/

type MemberDecorator = (target: Object, propertyKey: string | symbol, descriptor?: PropertyDescriptor) => PropertyDescriptor | void;

// feature test for Symbol support
const supportsSymbol = typeof Symbol === "function";
const toPrimitiveSymbol = supportsSymbol && typeof Symbol.toPrimitive !== "undefined" ? Symbol.toPrimitive : fail("Symbol.toPrimitive not found.");
const iteratorSymbol = supportsSymbol && typeof Symbol.iterator !== "undefined" ? Symbol.iterator : fail("Symbol.iterator not found.");

// Load global or shim versions of Map, Set, and WeakMap
const functionPrototype = Object.getPrototypeOf(Function);
const _Map: typeof Map = typeof Map === "function" && typeof Map.prototype.entries === "function" ? Map : fail("A valid Map constructor could not be found.");
const _Set: typeof Set = typeof Set === "function" && typeof Set.prototype.entries === "function" ? Set : fail("A valid Set constructor could not be found.");
const _WeakMap: typeof WeakMap = typeof WeakMap === "function" ? WeakMap : fail("A valid WeakMap constructor could not be found.");
const registrySymbol = supportsSymbol ? Symbol.for("@reflect-metadata:registry") : undefined;
const metadataRegistry = GetOrCreateMetadataRegistry();
const metadataProvider = CreateMetadataProvider(metadataRegistry);

/**
 * Applies a set of decorators to a target object.
 * @param decorators An array of decorators.
 * @param target The target object.
 * @returns The result of applying the provided decorators.
 * @remarks Decorators are applied in reverse order of their positions in the array.
 * @example
 *
 *     class Example { }
 *
 *     // constructor
 *     Example = Reflect.decorate(decoratorsArray, Example);
 *
 */
export function decorate(decorators: ClassDecorator[], target: Function): Function;

/**
 * Applies a set of decorators to a property of a target object.
 * @param decorators An array of decorators.
 * @param target The target object.
 * @param propertyKey The property key to decorate.
 * @param attributes A property descriptor.
 * @remarks Decorators are applied in reverse order.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         static staticMethod() { }
 *         method() { }
 *     }
 *
 *     // property (on constructor)
 *     Reflect.decorate(decoratorsArray, Example, "staticProperty");
 *
 *     // property (on prototype)
 *     Reflect.decorate(decoratorsArray, Example.prototype, "property");
 *
 *     // method (on constructor)
 *     Object.defineProperty(Example, "staticMethod",
 *         Reflect.decorate(decoratorsArray, Example, "staticMethod",
 *             Object.getOwnPropertyDescriptor(Example, "staticMethod")));
 *
 *     // method (on prototype)
 *     Object.defineProperty(Example.prototype, "method",
 *         Reflect.decorate(decoratorsArray, Example.prototype, "method",
 *             Object.getOwnPropertyDescriptor(Example.prototype, "method")));
 *
 */
export function decorate(decorators: (PropertyDecorator | MethodDecorator)[], target: any, propertyKey: string | symbol, attributes?: PropertyDescriptor | null): PropertyDescriptor | undefined;

/**
 * Applies a set of decorators to a property of a target object.
 * @param decorators An array of decorators.
 * @param target The target object.
 * @param propertyKey The property key to decorate.
 * @param attributes A property descriptor.
 * @remarks Decorators are applied in reverse order.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         static staticMethod() { }
 *         method() { }
 *     }
 *
 *     // property (on constructor)
 *     Reflect.decorate(decoratorsArray, Example, "staticProperty");
 *
 *     // property (on prototype)
 *     Reflect.decorate(decoratorsArray, Example.prototype, "property");
 *
 *     // method (on constructor)
 *     Object.defineProperty(Example, "staticMethod",
 *         Reflect.decorate(decoratorsArray, Example, "staticMethod",
 *             Object.getOwnPropertyDescriptor(Example, "staticMethod")));
 *
 *     // method (on prototype)
 *     Object.defineProperty(Example.prototype, "method",
 *         Reflect.decorate(decoratorsArray, Example.prototype, "method",
 *             Object.getOwnPropertyDescriptor(Example.prototype, "method")));
 *
 */
export function decorate(decorators: (PropertyDecorator | MethodDecorator)[], target: any, propertyKey: string | symbol, attributes: PropertyDescriptor): PropertyDescriptor;

/**
 * Applies a set of decorators to a property of a target object.
 * @param decorators An array of decorators.
 * @param target The target object.
 * @param propertyKey (Optional) The property key to decorate.
 * @param attributes (Optional) The property descriptor for the target key.
 * @remarks Decorators are applied in reverse order.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         constructor(p) { }
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // constructor
 *     Example = Reflect.decorate(decoratorsArray, Example);
 *
 *     // property (on constructor)
 *     Reflect.decorate(decoratorsArray, Example, "staticProperty");
 *
 *     // property (on prototype)
 *     Reflect.decorate(decoratorsArray, Example.prototype, "property");
 *
 *     // method (on constructor)
 *     Object.defineProperty(Example, "staticMethod",
 *         Reflect.decorate(decoratorsArray, Example, "staticMethod",
 *             Object.getOwnPropertyDescriptor(Example, "staticMethod")));
 *
 *     // method (on prototype)
 *     Object.defineProperty(Example.prototype, "method",
 *         Reflect.decorate(decoratorsArray, Example.prototype, "method",
 *             Object.getOwnPropertyDescriptor(Example.prototype, "method")));
 *
 */
export function decorate(decorators: (ClassDecorator | MemberDecorator)[], target: any, propertyKey?: string | symbol, attributes?: PropertyDescriptor | null): PropertyDescriptor | Function | undefined {
    if (!IsUndefined(propertyKey)) {
        if (!IsArray(decorators)) throw new TypeError();
        if (!IsObject(target)) throw new TypeError();
        if (!IsObject(attributes) && !IsUndefined(attributes) && !IsNull(attributes)) throw new TypeError();
        if (IsNull(attributes)) attributes = undefined;
        propertyKey = ToPropertyKey(propertyKey);
        return DecorateProperty(<MemberDecorator[]>decorators, target, propertyKey, attributes);
    }
    else {
        if (!IsArray(decorators)) throw new TypeError();
        if (!IsConstructor(target)) throw new TypeError();
        return DecorateConstructor(<ClassDecorator[]>decorators, <Function>target);
    }
}

// 4.1.2 Reflect.metadata(metadataKey, metadataValue)
// https://rbuckton.github.io/reflect-metadata/#reflect.metadata

/**
 * A default metadata decorator factory that can be used on a class, class member, or parameter.
 * @param metadataKey The key for the metadata entry.
 * @param metadataValue The value for the metadata entry.
 * @returns A decorator function.
 * @remarks
 * If `metadataKey` is already defined for the target and target key, the
 * metadataValue for that key will be overwritten.
 * @example
 *
 *     // constructor
 *     @Reflect.metadata(key, value)
 *     class Example {
 *     }
 *
 *     // property (on constructor, TypeScript only)
 *     class Example {
 *         @Reflect.metadata(key, value)
 *         static staticProperty;
 *     }
 *
 *     // property (on prototype, TypeScript only)
 *     class Example {
 *         @Reflect.metadata(key, value)
 *         property;
 *     }
 *
 *     // method (on constructor)
 *     class Example {
 *         @Reflect.metadata(key, value)
 *         static staticMethod() { }
 *     }
 *
 *     // method (on prototype)
 *     class Example {
 *         @Reflect.metadata(key, value)
 *         method() { }
 *     }
 *
 */
export function metadata(metadataKey: any, metadataValue: any): { (target: Function): void; (target: any, propertyKey: string | symbol): void; } {
    if (typeof Reflect !== "undefined" && typeof Reflect.metadata === "function" && Reflect.metadata !== metadata) {
        return Reflect.metadata(metadataKey, metadataValue);
    }
    function decorator(target: Function): void;
    function decorator(target: any, propertyKey: string | symbol): void;
    function decorator(target: any, propertyKey?: string | symbol): void {
        if (!IsObject(target)) throw new TypeError();
        if (!IsUndefined(propertyKey) && !IsPropertyKey(propertyKey)) throw new TypeError();
        OrdinaryDefineOwnMetadata(metadataKey, metadataValue, target, propertyKey);
    }
    return decorator;
}

// 4.1.3 Reflect.defineMetadata(metadataKey, metadataValue, target [, propertyKey])
// https://rbuckton.github.io/reflect-metadata/#reflect.definemetadata

/**
 * Define a unique metadata entry on the target.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param metadataValue A value that contains attached metadata.
 * @param target The target object on which to define metadata.
 * @example
 *
 *     class Example {
 *     }
 *
 *     // constructor
 *     Reflect.defineMetadata("custom:annotation", options, Example);
 *
 *     // decorator factory as metadata-producing annotation.
 *     function MyAnnotation(options): ClassDecorator {
 *         return target => Reflect.defineMetadata("custom:annotation", options, target);
 *     }
 *
 */
export function defineMetadata(metadataKey: any, metadataValue: any, target: any): void;

/**
 * Define a unique metadata entry on the target.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param metadataValue A value that contains attached metadata.
 * @param target The target object on which to define metadata.
 * @param propertyKey The property key for the target.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // property (on constructor)
 *     Reflect.defineMetadata("custom:annotation", Number, Example, "staticProperty");
 *
 *     // property (on prototype)
 *     Reflect.defineMetadata("custom:annotation", Number, Example.prototype, "property");
 *
 *     // method (on constructor)
 *     Reflect.defineMetadata("custom:annotation", Number, Example, "staticMethod");
 *
 *     // method (on prototype)
 *     Reflect.defineMetadata("custom:annotation", Number, Example.prototype, "method");
 *
 *     // decorator factory as metadata-producing annotation.
 *     function MyAnnotation(options): PropertyDecorator {
 *         return (target, key) => Reflect.defineMetadata("custom:annotation", options, target, key);
 *     }
 *
 */
export function defineMetadata(metadataKey: any, metadataValue: any, target: any, propertyKey: string | symbol): void;

/**
 * Define a unique metadata entry on the target.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param metadataValue A value that contains attached metadata.
 * @param target The target object on which to define metadata.
 * @param propertyKey (Optional) The property key for the target.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         constructor(p) { }
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // constructor
 *     Reflect.defineMetadata("custom:annotation", options, Example);
 *
 *     // property (on constructor)
 *     Reflect.defineMetadata("custom:annotation", options, Example, "staticProperty");
 *
 *     // property (on prototype)
 *     Reflect.defineMetadata("custom:annotation", options, Example.prototype, "property");
 *
 *     // method (on constructor)
 *     Reflect.defineMetadata("custom:annotation", options, Example, "staticMethod");
 *
 *     // method (on prototype)
 *     Reflect.defineMetadata("custom:annotation", options, Example.prototype, "method");
 *
 *     // decorator factory as metadata-producing annotation.
 *     function MyAnnotation(options): Decorator {
 *         return (target, key?) => Reflect.defineMetadata("custom:annotation", options, target, key);
 *     }
 *
 */
export function defineMetadata(metadataKey: any, metadataValue: any, target: any, propertyKey?: string | symbol): void {
    if (!IsObject(target)) throw new TypeError();
    if (!IsUndefined(propertyKey)) propertyKey = ToPropertyKey(propertyKey);
    return OrdinaryDefineOwnMetadata(metadataKey, metadataValue, target, propertyKey);
}

// 4.1.4 Reflect.hasMetadata(metadataKey, target [, propertyKey])
// https://rbuckton.github.io/reflect-metadata/#reflect.hasmetadata

/**
 * Gets a value indicating whether the target object or its prototype chain has the provided metadata key defined.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @returns `true` if the metadata key was defined on the target object or its prototype chain; otherwise, `false`.
 * @example
 *
 *     class Example {
 *     }
 *
 *     // constructor
 *     result = Reflect.hasMetadata("custom:annotation", Example);
 *
 */
export function hasMetadata(metadataKey: any, target: any): boolean;

/**
 * Gets a value indicating whether the target object or its prototype chain has the provided metadata key defined.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey The property key for the target.
 * @returns `true` if the metadata key was defined on the target object or its prototype chain; otherwise, `false`.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // property (on constructor)
 *     result = Reflect.hasMetadata("custom:annotation", Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.hasMetadata("custom:annotation", Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.hasMetadata("custom:annotation", Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.hasMetadata("custom:annotation", Example.prototype, "method");
 *
 */
export function hasMetadata(metadataKey: any, target: any, propertyKey: string | symbol): boolean;

/**
 * Gets a value indicating whether the target object or its prototype chain has the provided metadata key defined.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey (Optional) The property key for the target.
 * @returns `true` if the metadata key was defined on the target object or its prototype chain; otherwise, `false`.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         constructor(p) { }
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // constructor
 *     result = Reflect.hasMetadata("custom:annotation", Example);
 *
 *     // property (on constructor)
 *     result = Reflect.hasMetadata("custom:annotation", Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.hasMetadata("custom:annotation", Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.hasMetadata("custom:annotation", Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.hasMetadata("custom:annotation", Example.prototype, "method");
 *
 */
export function hasMetadata(metadataKey: any, target: any, propertyKey?: string | symbol): boolean {
    if (!IsObject(target)) throw new TypeError();
    if (!IsUndefined(propertyKey)) propertyKey = ToPropertyKey(propertyKey);
    return OrdinaryHasMetadata(metadataKey, target, propertyKey);
}

// 4.1.5 Reflect.hasOwnMetadata(metadataKey, target [, propertyKey])
// https://rbuckton.github.io/reflect-metadata/#reflect-hasownmetadata

/**
 * Gets a value indicating whether the target object has the provided metadata key defined.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @returns `true` if the metadata key was defined on the target object; otherwise, `false`.
 * @example
 *
 *     class Example {
 *     }
 *
 *     // constructor
 *     result = Reflect.hasOwnMetadata("custom:annotation", Example);
 *
 */
export function hasOwnMetadata(metadataKey: any, target: any): boolean;

/**
 * Gets a value indicating whether the target object has the provided metadata key defined.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey The property key for the target.
 * @returns `true` if the metadata key was defined on the target object; otherwise, `false`.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // property (on constructor)
 *     result = Reflect.hasOwnMetadata("custom:annotation", Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.hasOwnMetadata("custom:annotation", Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.hasOwnMetadata("custom:annotation", Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.hasOwnMetadata("custom:annotation", Example.prototype, "method");
 *
 */
export function hasOwnMetadata(metadataKey: any, target: any, propertyKey: string | symbol): boolean;

/**
 * Gets a value indicating whether the target object has the provided metadata key defined.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey (Optional) The property key for the target.
 * @returns `true` if the metadata key was defined on the target object; otherwise, `false`.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         constructor(p) { }
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // constructor
 *     result = Reflect.hasOwnMetadata("custom:annotation", Example);
 *
 *     // property (on constructor)
 *     result = Reflect.hasOwnMetadata("custom:annotation", Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.hasOwnMetadata("custom:annotation", Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.hasOwnMetadata("custom:annotation", Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.hasOwnMetadata("custom:annotation", Example.prototype, "method");
 *
 */
export function hasOwnMetadata(metadataKey: any, target: any, propertyKey?: string | symbol): boolean {
    if (!IsObject(target)) throw new TypeError();
    if (!IsUndefined(propertyKey)) propertyKey = ToPropertyKey(propertyKey);
    return OrdinaryHasOwnMetadata(metadataKey, target, propertyKey);
}

// 4.1.6 Reflect.getMetadata(metadataKey, target [, propertyKey])
// https://rbuckton.github.io/reflect-metadata/#reflect-getmetadata

/**
 * Gets the metadata value for the provided metadata key on the target object or its prototype chain.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @returns The metadata value for the metadata key if found; otherwise, `undefined`.
 * @example
 *
 *     class Example {
 *     }
 *
 *     // constructor
 *     result = Reflect.getMetadata("custom:annotation", Example);
 *
 */
export function getMetadata(metadataKey: any, target: any): any;

/**
 * Gets the metadata value for the provided metadata key on the target object or its prototype chain.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey The property key for the target.
 * @returns The metadata value for the metadata key if found; otherwise, `undefined`.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // property (on constructor)
 *     result = Reflect.getMetadata("custom:annotation", Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.getMetadata("custom:annotation", Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.getMetadata("custom:annotation", Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.getMetadata("custom:annotation", Example.prototype, "method");
 *
 */
export function getMetadata(metadataKey: any, target: any, propertyKey: string | symbol): any;

/**
 * Gets the metadata value for the provided metadata key on the target object or its prototype chain.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey (Optional) The property key for the target.
 * @returns The metadata value for the metadata key if found; otherwise, `undefined`.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         constructor(p) { }
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // constructor
 *     result = Reflect.getMetadata("custom:annotation", Example);
 *
 *     // property (on constructor)
 *     result = Reflect.getMetadata("custom:annotation", Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.getMetadata("custom:annotation", Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.getMetadata("custom:annotation", Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.getMetadata("custom:annotation", Example.prototype, "method");
 *
 */
export function getMetadata(metadataKey: any, target: any, propertyKey?: string | symbol): any {
    if (!IsObject(target)) throw new TypeError();
    if (!IsUndefined(propertyKey)) propertyKey = ToPropertyKey(propertyKey);
    return OrdinaryGetMetadata(metadataKey, target, propertyKey);
}

// 4.1.7 Reflect.getOwnMetadata(metadataKey, target [, propertyKey])
// https://rbuckton.github.io/reflect-metadata/#reflect-getownmetadata

/**
 * Gets the metadata value for the provided metadata key on the target object.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @returns The metadata value for the metadata key if found; otherwise, `undefined`.
 * @example
 *
 *     class Example {
 *     }
 *
 *     // constructor
 *     result = Reflect.getOwnMetadata("custom:annotation", Example);
 *
 */
export function getOwnMetadata(metadataKey: any, target: any): any;

/**
 * Gets the metadata value for the provided metadata key on the target object.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey The property key for the target.
 * @returns The metadata value for the metadata key if found; otherwise, `undefined`.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // property (on constructor)
 *     result = Reflect.getOwnMetadata("custom:annotation", Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.getOwnMetadata("custom:annotation", Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.getOwnMetadata("custom:annotation", Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.getOwnMetadata("custom:annotation", Example.prototype, "method");
 *
 */
export function getOwnMetadata(metadataKey: any, target: any, propertyKey: string | symbol): any;

/**
 * Gets the metadata value for the provided metadata key on the target object.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey (Optional) The property key for the target.
 * @returns The metadata value for the metadata key if found; otherwise, `undefined`.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         constructor(p) { }
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // constructor
 *     result = Reflect.getOwnMetadata("custom:annotation", Example);
 *
 *     // property (on constructor)
 *     result = Reflect.getOwnMetadata("custom:annotation", Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.getOwnMetadata("custom:annotation", Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.getOwnMetadata("custom:annotation", Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.getOwnMetadata("custom:annotation", Example.prototype, "method");
 *
 */
export function getOwnMetadata(metadataKey: any, target: any, propertyKey?: string | symbol): any {
    if (!IsObject(target)) throw new TypeError();
    if (!IsUndefined(propertyKey)) propertyKey = ToPropertyKey(propertyKey);
    return OrdinaryGetOwnMetadata(metadataKey, target, propertyKey);
}

// 4.1.8 Reflect.getMetadataKeys(target [, propertyKey])
// https://rbuckton.github.io/reflect-metadata/#reflect-getmetadatakeys

/**
 * Gets the metadata keys defined on the target object or its prototype chain.
 * @param target The target object on which the metadata is defined.
 * @returns An array of unique metadata keys.
 * @example
 *
 *     class Example {
 *     }
 *
 *     // constructor
 *     result = Reflect.getMetadataKeys(Example);
 *
 */
export function getMetadataKeys(target: any): any[];

/**
 * Gets the metadata keys defined on the target object or its prototype chain.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey The property key for the target.
 * @returns An array of unique metadata keys.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // property (on constructor)
 *     result = Reflect.getMetadataKeys(Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.getMetadataKeys(Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.getMetadataKeys(Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.getMetadataKeys(Example.prototype, "method");
 *
 */
export function getMetadataKeys(target: any, propertyKey: string | symbol): any[];

/**
 * Gets the metadata keys defined on the target object or its prototype chain.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey (Optional) The property key for the target.
 * @returns An array of unique metadata keys.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         constructor(p) { }
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // constructor
 *     result = Reflect.getMetadataKeys(Example);
 *
 *     // property (on constructor)
 *     result = Reflect.getMetadataKeys(Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.getMetadataKeys(Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.getMetadataKeys(Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.getMetadataKeys(Example.prototype, "method");
 *
 */
export function getMetadataKeys(target: any, propertyKey?: string | symbol): any[] {
    if (!IsObject(target)) throw new TypeError();
    if (!IsUndefined(propertyKey)) propertyKey = ToPropertyKey(propertyKey);
    return OrdinaryMetadataKeys(target, propertyKey);
}

// 4.1.9 Reflect.getOwnMetadataKeys(target [, propertyKey])
// https://rbuckton.github.io/reflect-metadata/#reflect-getownmetadata

/**
 * Gets the unique metadata keys defined on the target object.
 * @param target The target object on which the metadata is defined.
 * @returns An array of unique metadata keys.
 * @example
 *
 *     class Example {
 *     }
 *
 *     // constructor
 *     result = Reflect.getOwnMetadataKeys(Example);
 *
 */
export function getOwnMetadataKeys(target: any): any[];

/**
 * Gets the unique metadata keys defined on the target object.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey The property key for the target.
 * @returns An array of unique metadata keys.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // property (on constructor)
 *     result = Reflect.getOwnMetadataKeys(Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.getOwnMetadataKeys(Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.getOwnMetadataKeys(Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.getOwnMetadataKeys(Example.prototype, "method");
 *
 */
export function getOwnMetadataKeys(target: any, propertyKey: string | symbol): any[];

/**
 * Gets the unique metadata keys defined on the target object.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey (Optional) The property key for the target.
 * @returns An array of unique metadata keys.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         constructor(p) { }
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // constructor
 *     result = Reflect.getOwnMetadataKeys(Example);
 *
 *     // property (on constructor)
 *     result = Reflect.getOwnMetadataKeys(Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.getOwnMetadataKeys(Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.getOwnMetadataKeys(Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.getOwnMetadataKeys(Example.prototype, "method");
 *
 */
export function getOwnMetadataKeys(target: any, propertyKey?: string | symbol): any[] {
    if (!IsObject(target)) throw new TypeError();
    if (!IsUndefined(propertyKey)) propertyKey = ToPropertyKey(propertyKey);
    return OrdinaryOwnMetadataKeys(target, propertyKey);
}

// 4.1.10 Reflect.deleteMetadata(metadataKey, target [, propertyKey])
// https://rbuckton.github.io/reflect-metadata/#reflect-deletemetadata

/**
 * Deletes the metadata entry from the target object with the provided key.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @returns `true` if the metadata entry was found and deleted; otherwise, false.
 * @example
 *
 *     class Example {
 *     }
 *
 *     // constructor
 *     result = Reflect.deleteMetadata("custom:annotation", Example);
 *
 */
export function deleteMetadata(metadataKey: any, target: any): boolean;

/**
 * Deletes the metadata entry from the target object with the provided key.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey The property key for the target.
 * @returns `true` if the metadata entry was found and deleted; otherwise, false.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // property (on constructor)
 *     result = Reflect.deleteMetadata("custom:annotation", Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.deleteMetadata("custom:annotation", Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.deleteMetadata("custom:annotation", Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.deleteMetadata("custom:annotation", Example.prototype, "method");
 *
 */
export function deleteMetadata(metadataKey: any, target: any, propertyKey: string | symbol): boolean;

/**
 * Deletes the metadata entry from the target object with the provided key.
 * @param metadataKey A key used to store and retrieve metadata.
 * @param target The target object on which the metadata is defined.
 * @param propertyKey (Optional) The property key for the target.
 * @returns `true` if the metadata entry was found and deleted; otherwise, false.
 * @example
 *
 *     class Example {
 *         // property declarations are not part of ES6, though they are valid in TypeScript:
 *         // static staticProperty;
 *         // property;
 *
 *         constructor(p) { }
 *         static staticMethod(p) { }
 *         method(p) { }
 *     }
 *
 *     // constructor
 *     result = Reflect.deleteMetadata("custom:annotation", Example);
 *
 *     // property (on constructor)
 *     result = Reflect.deleteMetadata("custom:annotation", Example, "staticProperty");
 *
 *     // property (on prototype)
 *     result = Reflect.deleteMetadata("custom:annotation", Example.prototype, "property");
 *
 *     // method (on constructor)
 *     result = Reflect.deleteMetadata("custom:annotation", Example, "staticMethod");
 *
 *     // method (on prototype)
 *     result = Reflect.deleteMetadata("custom:annotation", Example.prototype, "method");
 *
 */
export function deleteMetadata(metadataKey: any, target: any, propertyKey?: string | symbol): boolean {
    if (!IsObject(target)) throw new TypeError();
    if (!IsUndefined(propertyKey)) propertyKey = ToPropertyKey(propertyKey);
    const provider = GetMetadataProvider(target, propertyKey, /*Create*/ false);
    if (IsUndefined(provider)) return false;
    return provider.OrdinaryDeleteMetadata(metadataKey, target, propertyKey);
}

function DecorateConstructor(decorators: ClassDecorator[], target: Function): Function {
    for (let i = decorators.length - 1; i >= 0; --i) {
        const decorator = decorators[i];
        const decorated = decorator(target);
        if (!IsUndefined(decorated) && !IsNull(decorated)) {
            if (!IsConstructor(decorated)) throw new TypeError();
            target = <Function>decorated;
        }
    }
    return target;
}

function DecorateProperty(decorators: MemberDecorator[], target: any, propertyKey: string | symbol, descriptor: PropertyDescriptor | undefined): PropertyDescriptor | undefined {
    for (let i = decorators.length - 1; i >= 0; --i) {
        const decorator = decorators[i];
        const decorated = decorator(target, propertyKey, descriptor);
        if (!IsUndefined(decorated) && !IsNull(decorated)) {
            if (!IsObject(decorated)) throw new TypeError();
            descriptor = <PropertyDescriptor>decorated;
        }
    }
    return descriptor;
}

// 3.1.1.1 OrdinaryHasMetadata(MetadataKey, O, P)
// https://rbuckton.github.io/reflect-metadata/#ordinaryhasmetadata
function OrdinaryHasMetadata(MetadataKey: any, O: any, P: string | symbol | undefined): boolean {
    const hasOwn = OrdinaryHasOwnMetadata(MetadataKey, O, P);
    if (hasOwn) return true;
    const parent = OrdinaryGetPrototypeOf(O);
    if (!IsNull(parent)) return OrdinaryHasMetadata(MetadataKey, parent, P);
    return false;
}

// 3.1.2.1 OrdinaryHasOwnMetadata(MetadataKey, O, P)
// https://rbuckton.github.io/reflect-metadata/#ordinaryhasownmetadata
function OrdinaryHasOwnMetadata(MetadataKey: any, O: any, P: string | symbol | undefined): boolean {
    const provider = GetMetadataProvider(O, P, /*Create*/ false);
    if (IsUndefined(provider)) return false;
    return ToBoolean(provider.OrdinaryHasOwnMetadata(MetadataKey, O, P));
}

// 3.1.3.1 OrdinaryGetMetadata(MetadataKey, O, P)
// https://rbuckton.github.io/reflect-metadata/#ordinarygetmetadata
function OrdinaryGetMetadata(MetadataKey: any, O: any, P: string | symbol | undefined): any {
    const hasOwn = OrdinaryHasOwnMetadata(MetadataKey, O, P);
    if (hasOwn) return OrdinaryGetOwnMetadata(MetadataKey, O, P);
    const parent = OrdinaryGetPrototypeOf(O);
    if (!IsNull(parent)) return OrdinaryGetMetadata(MetadataKey, parent, P);
    return undefined;
}

// 3.1.4.1 OrdinaryGetOwnMetadata(MetadataKey, O, P)
// https://rbuckton.github.io/reflect-metadata/#ordinarygetownmetadata
function OrdinaryGetOwnMetadata(MetadataKey: any, O: any, P: string | symbol | undefined): any {
    const provider = GetMetadataProvider(O, P, /*Create*/ false);
    if (IsUndefined(provider)) return;
    return provider.OrdinaryGetOwnMetadata(MetadataKey, O, P);
}

// 3.1.5.1 OrdinaryDefineOwnMetadata(MetadataKey, MetadataValue, O, P)
// https://rbuckton.github.io/reflect-metadata/#ordinarydefineownmetadata
function OrdinaryDefineOwnMetadata(MetadataKey: any, MetadataValue: any, O: any, P: string | symbol | undefined): void {
    const provider = GetMetadataProvider(O, P, /*Create*/ true);
    provider.OrdinaryDefineOwnMetadata(MetadataKey, MetadataValue, O, P);
}

// 3.1.6.1 OrdinaryMetadataKeys(O, P)
// https://rbuckton.github.io/reflect-metadata/#ordinarymetadatakeys
function OrdinaryMetadataKeys(O: any, P: string | symbol | undefined): any[] {
    const ownKeys = OrdinaryOwnMetadataKeys(O, P);
    const parent = OrdinaryGetPrototypeOf(O);
    if (parent === null) return ownKeys;
    const parentKeys = OrdinaryMetadataKeys(parent, P);
    if (parentKeys.length <= 0) return ownKeys;
    if (ownKeys.length <= 0) return parentKeys;
    const set = new _Set<any>();
    const keys: any[] = [];
    for (const key of ownKeys) {
        const hasKey = set.has(key);
        if (!hasKey) {
            set.add(key);
            keys.push(key);
        }
    }
    for (const key of parentKeys) {
        const hasKey = set.has(key);
        if (!hasKey) {
            set.add(key);
            keys.push(key);
        }
    }
    return keys;
}

// 3.1.7.1 OrdinaryOwnMetadataKeys(O, P)
// https://rbuckton.github.io/reflect-metadata/#ordinaryownmetadatakeys
function OrdinaryOwnMetadataKeys(O: any, P: string | symbol | undefined): any[] {
    const provider = GetMetadataProvider(O, P, /*create*/ false);
    if (!provider) {
        return [];
    }
    return provider.OrdinaryOwnMetadataKeys(O, P);
}

// 6 ECMAScript Data Types and Values
// https://tc39.github.io/ecma262/#sec-ecmascript-data-types-and-values
function Type(x: any): Tag {
    if (x === null) return Tag.Null;
    switch (typeof x) {
        case "undefined": return Tag.Undefined;
        case "boolean": return Tag.Boolean;
        case "string": return Tag.String;
        case "symbol": return Tag.Symbol;
        case "number": return Tag.Number;
        case "object": return x === null ? Tag.Null : Tag.Object;
        default: return Tag.Object;
    }
}

// 6.1 ECMAScript Language Types
// https://tc39.github.io/ecma262/#sec-ecmascript-language-types
const enum Tag {
    Undefined,
    Null,
    Boolean,
    String,
    Symbol,
    Number,
    Object
}

// 6.1.1 The Undefined Type
// https://tc39.github.io/ecma262/#sec-ecmascript-language-types-undefined-type
function IsUndefined(x: any): x is undefined {
    return x === undefined;
}

// 6.1.2 The Null Type
// https://tc39.github.io/ecma262/#sec-ecmascript-language-types-null-type
function IsNull(x: any): x is null {
    return x === null;
}

// 6.1.5 The Symbol Type
// https://tc39.github.io/ecma262/#sec-ecmascript-language-types-symbol-type
function IsSymbol(x: any): x is symbol {
    return typeof x === "symbol";
}

// 6.1.7 The Object Type
// https://tc39.github.io/ecma262/#sec-object-type
function IsObject<T>(x: T | undefined | null | boolean | string | symbol | number): x is T {
    return typeof x === "object" ? x !== null : typeof x === "function";
}

// 7.1 Type Conversion
// https://tc39.github.io/ecma262/#sec-type-conversion

// 7.1.1 ToPrimitive(input [, PreferredType])
// https://tc39.github.io/ecma262/#sec-toprimitive
function ToPrimitive(input: any, PreferredType?: Tag): undefined | null | boolean | string | symbol | number {
    switch (Type(input)) {
        case Tag.Undefined: return input;
        case Tag.Null: return input;
        case Tag.Boolean: return input;
        case Tag.String: return input;
        case Tag.Symbol: return input;
        case Tag.Number: return input;
    }
    const hint: "string" | "number" | "default" = PreferredType === Tag.String ? "string" : PreferredType === Tag.Number ? "number" : "default";
    const exoticToPrim = GetMethod(input, toPrimitiveSymbol);
    if (exoticToPrim !== undefined) {
        const result = exoticToPrim.call(input, hint);
        if (IsObject(result)) throw new TypeError();
        return result;
    }
    return OrdinaryToPrimitive(input, hint === "default" ? "number" : hint);
}

// 7.1.1.1 OrdinaryToPrimitive(O, hint)
// https://tc39.github.io/ecma262/#sec-ordinarytoprimitive
function OrdinaryToPrimitive(O: any, hint: "string" | "number"): undefined | null | boolean | string | symbol | number {
    if (hint === "string") {
        const toString = O.toString;
        if (IsCallable(toString)) {
            const result = toString.call(O);
            if (!IsObject(result)) return result;
        }
        const valueOf = O.valueOf;
        if (IsCallable(valueOf)) {
            const result = valueOf.call(O);
            if (!IsObject(result)) return result;
        }
    }
    else {
        const valueOf = O.valueOf;
        if (IsCallable(valueOf)) {
            const result = valueOf.call(O);
            if (!IsObject(result)) return result;
        }
        const toString = O.toString;
        if (IsCallable(toString)) {
            const result = toString.call(O);
            if (!IsObject(result)) return result;
        }
    }
    throw new TypeError();
}

// 7.1.2 ToBoolean(argument)
// https://tc39.github.io/ecma262/2016/#sec-toboolean
function ToBoolean(argument: any): boolean {
    return !!argument;
}

// 7.1.12 ToString(argument)
// https://tc39.github.io/ecma262/#sec-tostring
function ToString(argument: any): string {
    return "" + argument;
}

// 7.1.14 ToPropertyKey(argument)
// https://tc39.github.io/ecma262/#sec-topropertykey
function ToPropertyKey(argument: any): string | symbol {
    const key = ToPrimitive(argument, Tag.String);
    if (IsSymbol(key)) return key;
    return ToString(key);
}

// 7.2 Testing and Comparison Operations
// https://tc39.github.io/ecma262/#sec-testing-and-comparison-operations

// 7.2.2 IsArray(argument)
// https://tc39.github.io/ecma262/#sec-isarray
function IsArray(argument: any): argument is any[] {
    return Array.isArray
        ? Array.isArray(argument)
        : argument instanceof Object
            ? argument instanceof Array
            : Object.prototype.toString.call(argument) === "[object Array]";
}

// 7.2.3 IsCallable(argument)
// https://tc39.github.io/ecma262/#sec-iscallable
function IsCallable(argument: any): argument is Function {
    // NOTE: This is an approximation as we cannot check for [[Call]] internal method.
    return typeof argument === "function";
}

// 7.2.4 IsConstructor(argument)
// https://tc39.github.io/ecma262/#sec-isconstructor
function IsConstructor(argument: any): argument is Function {
    // NOTE: This is an approximation as we cannot check for [[Construct]] internal method.
    return typeof argument === "function";
}

// 7.2.7 IsPropertyKey(argument)
// https://tc39.github.io/ecma262/#sec-ispropertykey
function IsPropertyKey(argument: any): argument is string | symbol {
    switch (Type(argument)) {
        case Tag.String: return true;
        case Tag.Symbol: return true;
        default: return false;
    }
}

// 7.3 Operations on Objects
// https://tc39.github.io/ecma262/#sec-operations-on-objects

// 7.3.9 GetMethod(V, P)
// https://tc39.github.io/ecma262/#sec-getmethod
function GetMethod(V: any, P: any): Function | undefined {
    const func = V[P];
    if (func === undefined || func === null) return undefined;
    if (!IsCallable(func)) throw new TypeError();
    return func;
}

// 7.4 Operations on Iterator Objects
// https://tc39.github.io/ecma262/#sec-operations-on-iterator-objects

function GetIterator<T>(obj: Iterable<T>): Iterator<T> {
    const method = GetMethod(obj, iteratorSymbol);
    if (!IsCallable(method)) throw new TypeError(); // from Call
    const iterator = method.call(obj);
    if (!IsObject(iterator)) throw new TypeError();
    return iterator;
}

// 7.4.4 IteratorValue(iterResult)
// https://tc39.github.io/ecma262/2016/#sec-iteratorvalue
function IteratorValue<T>(iterResult: __IteratorResult<T>): T {
    return iterResult.value;
}

// 7.4.5 IteratorStep(iterator)
// https://tc39.github.io/ecma262/#sec-iteratorstep
function IteratorStep<T>(iterator: Iterator<T>): __IteratorResult<T> | false {
    const result = iterator.next();
    return result.done ? false : result;
}

// 7.4.6 IteratorClose(iterator, completion)
// https://tc39.github.io/ecma262/#sec-iteratorclose
function IteratorClose<T>(iterator: Iterator<T>) {
    const f = iterator["return"];
    if (f) f.call(iterator);
}

// 9.1 Ordinary Object Internal Methods and Internal Slots
// https://tc39.github.io/ecma262/#sec-ordinary-object-internal-methods-and-internal-slots

// 9.1.1.1 OrdinaryGetPrototypeOf(O)
// https://tc39.github.io/ecma262/#sec-ordinarygetprototypeof
function OrdinaryGetPrototypeOf(O: any): any {
    const proto = Object.getPrototypeOf(O);
    if (typeof O !== "function" || O === functionPrototype) return proto;

    // TypeScript doesn't set __proto__ in ES5, as it's non-standard.
    // Try to determine the superclass constructor. Compatible implementations
    // must either set __proto__ on a subclass constructor to the superclass constructor,
    // or ensure each class has a valid `constructor` property on its prototype that
    // points back to the constructor.

    // If this is not the same as Function.[[Prototype]], then this is definately inherited.
    // This is the case when in ES6 or when using __proto__ in a compatible browser.
    if (proto !== functionPrototype) return proto;

    // If the super prototype is Object.prototype, null, or undefined, then we cannot determine the heritage.
    const prototype = O.prototype;
    const prototypeProto = prototype && Object.getPrototypeOf(prototype);
    if (prototypeProto == null || prototypeProto === Object.prototype) return proto;

    // If the constructor was not a function, then we cannot determine the heritage.
    const constructor = prototypeProto.constructor;
    if (typeof constructor !== "function") return proto;

    // If we have some kind of self-reference, then we cannot determine the heritage.
    if (constructor === O) return proto;

    // we have a pretty good guess at the heritage.
    return constructor;
}

function fail(e: any): never {
    throw e;
}

// Global metadata registry
// - Allows `import "reflect-metadata"` and `import "reflect-metadata/no-conflict"` to interoperate.
// - Uses isolated metadata if `Reflect` is frozen before the registry can be installed.

/**
 * Creates a registry used to allow multiple `reflect-metadata` providers.
 */
function CreateMetadataRegistry(): MetadataRegistry {
    let fallback: MetadataProvider | undefined;
    if (!IsUndefined(registrySymbol) &&
        typeof Reflect !== "undefined" &&
        !(registrySymbol in Reflect) &&
        typeof Reflect.defineMetadata === "function") {
        // interoperate with older version of `reflect-metadata` that did not support a registry.
        fallback = CreateFallbackProvider(Reflect);
    }

    let first: MetadataProvider | undefined;
    let second: MetadataProvider | undefined;
    let rest: Set<MetadataProvider> | undefined;
    const targetProviderMap = new _WeakMap<object, Map<string | symbol | undefined, MetadataProvider>>();
    const registry: MetadataRegistry = {
        registerProvider,
        getProvider,
        setProvider,
    };
    return registry;

    function registerProvider(provider: MetadataProvider) {
        if (!Object.isExtensible(registry)) {
            throw new Error("Cannot add provider to a frozen registry.");
        }
        switch (true) {
            case fallback === provider: break;
            case IsUndefined(first): first = provider; break;
            case first === provider: break;
            case IsUndefined(second): second = provider; break;
            case second === provider: break;
            default:
                if (rest === undefined) rest = new _Set();
                rest.add(provider);
                break;
        }
    }

    function getProviderNoCache(O: object, P: string | symbol | undefined) {
        if (!IsUndefined(first)) {
            if (first.isProviderFor(O, P)) return first;
            if (!IsUndefined(second)) {
                if (second.isProviderFor(O, P)) return first;
                if (!IsUndefined(rest)) {
                    const iterator = GetIterator(rest);
                    while (true) {
                        const next = IteratorStep(iterator);
                        if (!next) {
                            return undefined;
                        }
                        const provider = IteratorValue(next);
                        if (provider.isProviderFor(O, P)) {
                            IteratorClose(iterator);
                            return provider;
                        }
                    }
                }
            }
        }
        if (!IsUndefined(fallback) && fallback.isProviderFor(O, P)) {
            return fallback;
        }
        return undefined;
    }

    function getProvider(O: object, P: string | symbol | undefined) {
        let providerMap = targetProviderMap.get(O);
        let provider: MetadataProvider | undefined;
        if (!IsUndefined(providerMap)) {
            provider = providerMap.get(P);
        }
        if (!IsUndefined(provider)) {
            return provider;
        }

        provider = getProviderNoCache(O, P);
        if (!IsUndefined(provider)) {
            if (IsUndefined(providerMap)) {
                providerMap = new _Map();
                targetProviderMap.set(O, providerMap);
            }
            providerMap.set(P, provider);
        }
        return provider;
    }

    function hasProvider(provider: MetadataProvider) {
        if (IsUndefined(provider)) throw new TypeError();
        return fallback === provider || first === provider || second === provider || !IsUndefined(rest) && rest.has(provider);
    }

    function setProvider(O: object, P: string | symbol | undefined, provider: MetadataProvider) {
        if (!hasProvider(provider)) {
            throw new Error("Metadata provider not registered.");
        }
        const existingProvider = getProvider(O, P);
        if (existingProvider !== provider) {
            if (!IsUndefined(existingProvider)) {
                return false;
            }
            let providerMap = targetProviderMap.get(O);
            if (IsUndefined(providerMap)) {
                providerMap = new _Map();
                targetProviderMap.set(O, providerMap);
            }
            providerMap.set(P, provider);
        }
        return true;
    }
}

/**
 * Gets or creates the shared registry of metadata providers.
 */
function GetOrCreateMetadataRegistry(): MetadataRegistry {
    let metadataRegistry: MetadataRegistry | undefined;
    if (!IsUndefined(registrySymbol) && IsObject(Reflect) && Object.isExtensible(Reflect)) {
        metadataRegistry = (Reflect as any)[registrySymbol] as MetadataRegistry | undefined;
    }
    if (IsUndefined(metadataRegistry)) {
        metadataRegistry = CreateMetadataRegistry();
    }
    if (!IsUndefined(registrySymbol) && IsObject(Reflect) && Object.isExtensible(Reflect)) {
        Object.defineProperty(Reflect, registrySymbol, {
            enumerable: false,
            configurable: false,
            writable: false,
            value: metadataRegistry
        });
    }
    return metadataRegistry;
}

function CreateMetadataProvider(registry: MetadataRegistry): MetadataProvider {
    // [[Metadata]] internal slot
    // https://rbuckton.github.io/reflect-metadata/#ordinary-object-internal-methods-and-internal-slots
    const metadata = new _WeakMap<any, Map<string | symbol | undefined, Map<any, any>>>();
    const provider: MetadataProvider = {
        isProviderFor(O, P) {
            const targetMetadata = metadata.get(O);
            if (IsUndefined(targetMetadata)) return false;
            return targetMetadata.has(P);
        },
        OrdinaryDefineOwnMetadata: OrdinaryDefineOwnMetadata,
        OrdinaryHasOwnMetadata: OrdinaryHasOwnMetadata,
        OrdinaryGetOwnMetadata: OrdinaryGetOwnMetadata,
        OrdinaryOwnMetadataKeys: OrdinaryOwnMetadataKeys,
        OrdinaryDeleteMetadata: OrdinaryDeleteMetadata,
    };
    metadataRegistry.registerProvider(provider);
    return provider;

    // 2.1.1 GetOrCreateMetadataMap(O, P, Create)
    // https://rbuckton.github.io/reflect-metadata/#getorcreatemetadatamap
    function GetOrCreateMetadataMap(O: object, P: string | symbol | undefined, Create: true): Map<any, any>;
    function GetOrCreateMetadataMap(O: object, P: string | symbol | undefined, Create: false): Map<any, any> | undefined;
    function GetOrCreateMetadataMap(O: object, P: string | symbol | undefined, Create: boolean) {
        let targetMetadata = metadata.get(O);
        let createdTargetMetadata = false;
        if (IsUndefined(targetMetadata)) {
            if (!Create) return undefined;
            targetMetadata = new _Map<string | symbol | undefined, Map<any, any>>();
            metadata.set(O, targetMetadata);
            createdTargetMetadata = true;
        }
        let metadataMap = targetMetadata.get(P);
        if (IsUndefined(metadataMap)) {
            if (!Create) return undefined;
            metadataMap = new _Map<any, any>();
            targetMetadata.set(P, metadataMap);
            if (!registry.setProvider(O, P, provider)) {
                targetMetadata.delete(P);
                if (createdTargetMetadata) {
                    metadata.delete(O);
                }
                throw new Error("Wrong provider for target.");
            }
        }
        return metadataMap;
    }

    // 3.1.2.1 OrdinaryHasOwnMetadata(MetadataKey, O, P)
    // https://rbuckton.github.io/reflect-metadata/#ordinaryhasownmetadata
    function OrdinaryHasOwnMetadata(MetadataKey: any, O: object, P: string | symbol | undefined): boolean {
        const metadataMap = GetOrCreateMetadataMap(O, P, /*Create*/ false);
        if (IsUndefined(metadataMap)) return false;
        return ToBoolean(metadataMap.has(MetadataKey));
    }

    // 3.1.4.1 OrdinaryGetOwnMetadata(MetadataKey, O, P)
    // https://rbuckton.github.io/reflect-metadata/#ordinarygetownmetadata
    function OrdinaryGetOwnMetadata(MetadataKey: any, O: object, P: string | symbol | undefined): any {
        const metadataMap = GetOrCreateMetadataMap(O, P, /*Create*/ false);
        if (IsUndefined(metadataMap)) return undefined;
        return metadataMap.get(MetadataKey);
    }

    // 3.1.5.1 OrdinaryDefineOwnMetadata(MetadataKey, MetadataValue, O, P)
    // https://rbuckton.github.io/reflect-metadata/#ordinarydefineownmetadata
    function OrdinaryDefineOwnMetadata(MetadataKey: any, MetadataValue: any, O: object, P: string | symbol | undefined): void {
        const metadataMap = GetOrCreateMetadataMap(O, P, /*Create*/ true);
        metadataMap.set(MetadataKey, MetadataValue);
    }

    // 3.1.7.1 OrdinaryOwnMetadataKeys(O, P)
    // https://rbuckton.github.io/reflect-metadata/#ordinaryownmetadatakeys
    function OrdinaryOwnMetadataKeys(O: any, P: string | symbol | undefined): any[] {
        const keys: any[] = [];
        const metadataMap = GetOrCreateMetadataMap(O, P, /*Create*/ false);
        if (IsUndefined(metadataMap)) return keys;
        const keysObj = metadataMap.keys();
        const iterator = GetIterator(keysObj);
        let k = 0;
        while (true) {
            const next = IteratorStep(iterator);
            if (!next) {
                keys.length = k;
                return keys;
            }
            const nextValue = IteratorValue(next);
            try {
                keys[k] = nextValue;
            }
            catch (e) {
                try {
                    IteratorClose(iterator);
                }
                finally {
                    throw e;
                }
            }
            k++;
        }
    }

    function OrdinaryDeleteMetadata(MetadataKey: any, O: object, P: string | symbol | undefined): boolean {
        const metadataMap = GetOrCreateMetadataMap(O, P, /*Create*/ false);
        if (IsUndefined(metadataMap)) return false;
        if (!metadataMap.delete(MetadataKey)) return false;
        if (metadataMap.size === 0) {
            const targetMetadata = metadata.get(O);
            if (!IsUndefined(targetMetadata)) {
                targetMetadata.delete(P);
                if (targetMetadata.size === 0) {
                    metadata.delete(targetMetadata);
                }
            }
        }
        return true;
    }
}

function CreateFallbackProvider(reflect: typeof Reflect): MetadataProvider {
    const { defineMetadata, hasOwnMetadata, getOwnMetadata, getOwnMetadataKeys, deleteMetadata } = reflect;
    const metadataOwner = new _WeakMap<object, Set<string | symbol | undefined>>();
    const provider: MetadataProvider = {
        isProviderFor(O, P) {
            let metadataPropertySet = metadataOwner.get(O);
            if (!IsUndefined(metadataPropertySet) && metadataPropertySet.has(P)) {
                return true;
            }
            if (getOwnMetadataKeys(O, P!).length) {
                if (IsUndefined(metadataPropertySet)) {
                    metadataPropertySet = new _Set();
                    metadataOwner.set(O, metadataPropertySet);
                }
                metadataPropertySet.add(P);
                return true;
            }
            return false;
        },
        OrdinaryDefineOwnMetadata: defineMetadata,
        OrdinaryHasOwnMetadata: hasOwnMetadata,
        OrdinaryGetOwnMetadata: getOwnMetadata,
        OrdinaryOwnMetadataKeys: getOwnMetadataKeys,
        OrdinaryDeleteMetadata: deleteMetadata,
    };
    return provider;
}

function GetMetadataProvider(O: object, P: string | symbol | undefined, Create: true): MetadataProvider;
function GetMetadataProvider(O: object, P: string | symbol | undefined, Create: false): MetadataProvider | undefined;
/**
 * Gets the metadata provider for an object. If the object has no metadata provider and this is for a create operation,
 * then this module's metadata provider is assigned to the object.
 */
function GetMetadataProvider(O: object, P: string | symbol | undefined, Create: boolean): MetadataProvider | undefined {
    const registeredProvider = metadataRegistry.getProvider(O, P);
    if (!IsUndefined(registeredProvider)) {
        return registeredProvider;
    }
    if (Create) {
        if (metadataRegistry.setProvider(O, P, metadataProvider)) {
            return metadataProvider;
        }
        throw new Error("Illegal state.");
    }
    return undefined;
}