ReflectLite.ts

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

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

    declare const global: any;
    declare const globalThis: any;
    declare const self: any;

    /**
      * 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 declare 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 declare 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 declare function decorate(decorators: (PropertyDecorator | MethodDecorator)[], target: any, propertyKey: string | symbol, attributes: PropertyDescriptor): PropertyDescriptor;

    /**
      * 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 declare function metadata(metadataKey: any, metadataValue: any): { (target: Function): void; (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.
      * @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 declare 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 declare function defineMetadata(metadataKey: any, metadataValue: any, target: any, propertyKey: string | symbol): void;

    /**
      * 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 declare 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 declare function hasMetadata(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.
      * @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 declare 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 declare function hasOwnMetadata(metadataKey: any, target: any, propertyKey: string | symbol): boolean;

    /**
      * 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 declare 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 declare function getMetadata(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.
      * @returns The metadata value for the metadata key if found; otherwise, `undefined`.
      * @example
      *
      *     class Example {
      *     }
      *
      *     // constructor
      *     result = Reflect.getOwnMetadata("custom:annotation", Example);
      *
      */
    export declare 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 declare function getOwnMetadata(metadataKey: any, 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.
      * @returns An array of unique metadata keys.
      * @example
      *
      *     class Example {
      *     }
      *
      *     // constructor
      *     result = Reflect.getMetadataKeys(Example);
      *
      */
    export declare 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 declare function getMetadataKeys(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.
      * @returns An array of unique metadata keys.
      * @example
      *
      *     class Example {
      *     }
      *
      *     // constructor
      *     result = Reflect.getOwnMetadataKeys(Example);
      *
      */
    export declare 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 declare function getOwnMetadataKeys(target: any, propertyKey: string | symbol): any[];

    /**
      * 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 declare 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 declare function deleteMetadata(metadataKey: any, target: any, propertyKey: string | symbol): boolean;

    (function (this: any, factory: (exporter: <K extends keyof typeof Reflect>(key: K, value: typeof Reflect[K]) => void, root: any) => void) {
        const root =
            typeof globalThis === "object" ? globalThis :
            typeof global === "object" ? global :
            typeof self === "object" ? self :
            typeof this === "object" ? this :
            sloppyModeThis();

        let exporter = makeExporter(Reflect);
        if (typeof root.Reflect !== "undefined") {
            exporter = makeExporter(root.Reflect, exporter);
        }

        factory(exporter, root);

        if (typeof root.Reflect === "undefined") {
            root.Reflect = Reflect;
        }

        function makeExporter(target: typeof Reflect, previous?: <K extends keyof typeof Reflect>(key: K, value: typeof Reflect[K]) => void) {
            return <K extends keyof typeof Reflect>(key: K, value: typeof Reflect[K]) => {
                Object.defineProperty(target, key, { configurable: true, writable: true, value });
                if (previous) previous(key, value);
            };
        }

        function sloppyModeThis(): never {
            throw new ReferenceError("globalThis could not be found. Please polyfill globalThis before loading this module.");
        }
    })
    (function (exporter, root) {
        // 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);

        function decorate(decorators: ClassDecorator[], target: Function): Function;
        function decorate(decorators: (PropertyDecorator | MethodDecorator)[], target: any, propertyKey: string | symbol, attributes?: PropertyDescriptor | null): PropertyDescriptor | undefined;
        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")));
         *
         */
        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);
            }
        }

        exporter("decorate", decorate);

        // 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() { }
         *     }
         *
         */
        function metadata(metadataKey: any, metadataValue: any) {
            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;
        }

        exporter("metadata", metadata);

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

        function defineMetadata(metadataKey: any, metadataValue: any, target: any): void;
        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);
         *     }
         *
         */
        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);
        }

        exporter("defineMetadata", defineMetadata);

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

        function hasMetadata(metadataKey: any, target: any): boolean;
        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");
         *
         */
        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);
        }

        exporter("hasMetadata", hasMetadata);

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

        function hasOwnMetadata(metadataKey: any, target: any): boolean;
        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");
         *
         */
        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);
        }

        exporter("hasOwnMetadata", hasOwnMetadata);

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

        function getMetadata(metadataKey: any, target: any): any;
        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");
         *
         */
        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);
        }

        exporter("getMetadata", getMetadata);

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

        function getOwnMetadata(metadataKey: any, target: any): any;
        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");
         *
         */
        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);
        }

        exporter("getOwnMetadata", getOwnMetadata);

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

        function getMetadataKeys(target: any): any[];
        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");
         *
         */
        function getMetadataKeys(target: any, propertyKey?: string | symbol): any[] {
            if (!IsObject(target)) throw new TypeError();
            if (!IsUndefined(propertyKey)) propertyKey = ToPropertyKey(propertyKey);
            return OrdinaryMetadataKeys(target, propertyKey);
        }

        exporter("getMetadataKeys", getMetadataKeys);

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

        function getOwnMetadataKeys(target: any): any[];
        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");
         *
         */
        function getOwnMetadataKeys(target: any, propertyKey?: string | symbol): any[] {
            if (!IsObject(target)) throw new TypeError();
            if (!IsUndefined(propertyKey)) propertyKey = ToPropertyKey(propertyKey);
            return OrdinaryOwnMetadataKeys(target, propertyKey);
        }

        exporter("getOwnMetadataKeys", getOwnMetadataKeys);

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

        function deleteMetadata(metadataKey: any, target: any): boolean;
        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");
         *
         */
        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);
        }

        exporter("deleteMetadata", deleteMetadata);

        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 root.Reflect !== "undefined" &&
                !(registrySymbol in root.Reflect) &&
                typeof root.Reflect.defineMetadata === "function") {
                // interoperate with older version of `reflect-metadata` that did not support a registry.
                fallback = CreateFallbackProvider(root.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 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(root.Reflect) && Object.isExtensible(root.Reflect)) {
                metadataRegistry = (root.Reflect as any)[registrySymbol] as MetadataRegistry | undefined;
            }
            if (IsUndefined(metadataRegistry)) {
                metadataRegistry = CreateMetadataRegistry();
            }
            if (!IsUndefined(registrySymbol) && IsObject(root.Reflect) && Object.isExtensible(root.Reflect)) {
                Object.defineProperty(root.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;
        }
    });
}