spaghiajoeojo / express-beans

import { logger } from '@/core';

function getSingleton(singletonClass: any) {

  if (singletonClass) {

    if (singletonClass.instance) {

      return singletonClass.instance;

    }

    throw new Error(`Cannot get instance from ${singletonClass.name}. Make sure that ${singletonClass.name} has @Bean as class decorator`);

  }

  throw new Error('Please specify the type of Bean. Example: @InjectBean(BeanClass)');

}

/**

 * Gets singleton instance by its static property

 * @decorator

 * @param singletonClass

 */

export function InjectBean<T>(singletonClass: T) {

  return (_value: any, context: ClassFieldDecoratorContext) => () => {

    logger.debug(`initializing ${String(context.name)} with instance of bean ${getSingleton(singletonClass).className}`);

    return getSingleton(singletonClass);

  };

}