{
    /* Experimental Options */

    /* Enables experimental support for ES7 decorators. */
    "experimentalDecorators": true,

    /* Enables experimental support for emitting type metadata for decorators. */
    "emitDecoratorMetadata": true,
}

@sealed
class Raccoon {
    isFuzzy: boolean = true;
    shouldPet: boolean = false;
}

function sealed(constructor: Function) {
    Object.seal(constructor);
    Object.seal(constructor.prototype);
}

class Bear {
    @deprecate
    hibernate(): void {
        // ...
    }
}

function deprecate(
    target: any, 
    propertyKey: string, 
    descriptor: PropertyDescriptor
) {
    const message = 'This will be removed in future versions';
    return {
        ...descriptor,
        value: () => {
            console.warn(`DEPRECATED: ${key}: ${message}`;
            return descriptor.value.apply(this, arguments);
        }
    };
}

class Bear {
    @validate
    growl(@required volume: 1 | 11): void {
        if (volume === 1) {
            console.log('Grrraaaa');
        } else if (volume === 11) {
            console.log('GRRRRAAAAAWWHRHHF');
        }
    }
}

import "reflect-metadata";

const requiredMetadataKey = Symbol("required");

function required(target: Object, propertyKey: string | symbol, parameterIndex: number) {
    let existingReqParams: number[] = Reflect.getOwnMetadata(
        requiredMetadataKey, 
        target, 
        propertyKey
    ) || [];
    existingReqParams.push(parameterIndex);
    Reflect.defineMetadata(requiredMetadataKey, existingReqParams, target, propertyKey);
}

let cub = {};

cub.name = 'Rupert';
// Defaults - created by assignment

{ 
    configurable: true, 
    enumerable: true, 
    writable: true,
    value: 'Rupert'
}

Object.defineProperty(cub, 'name', {value: 'Rupert'});
// Defaults - created with Object.defineProperty

{ 
    configurable: false, 
    enumerable: false, 
    writable: false,
    value: 'Rupert'
}