pure js IOC container

amqp.js

import amqp from 'amqplib';

module.exports = {
  boot: async function () {
    return await amqp.connect('amqp://guest:guest@rabbitmq:5672');
  },
  close: (conn) => conn.close()
};

index.js

import ResourceManager from './ResourceManager';
import _ from 'lodash';

function createContainer (defs) {
  return new Proxy(new ResourceManager(_.toPairs(defs)), {
    get (target, name, receiver) {
      if (name === 'close') {
        return target.close.bind(target);
      }

      return target.get(name);
    }
  });
}

export const container = createContainer({
  amqp: require('./amqp'),
  mongo: require('./mongo')
});

mongo.js

import {MongoClient} from 'mongodb';

module.exports = {
  boot: async function () {
    return await MongoClient.connect('mongodb://mongodb/issue-api');
  },
  close: (conn) => conn.close()
};

ResourceManager.js

export default class ResourceManager {
  constructor (defs) {
    this._defs = new Map(defs);
    this._booted = new Map();
  }

  async get (name) {
    if (!this._defs.has(name)) {
      throw new Error(`There is no resource named "${name}".`);
    } else if (!this._booted.has(name)) {
      const def = this._defs.get(name);
      this._booted.set(name, await def.boot());
    }

    return this._booted.get(name);
  }

  close () {
    this._booted.forEach((resource, name) => {
      const def = this._defs.get(name);

      if (def.close) {
        def.close(resource);
      }
    });
  }
}

test.js

import {container} from './';

function createProgram () {
  const program = require('commander');
  program.command('test').action(handler);

  return program;
}

async function handler () {
  const amqp = await container.amqp;
  const mongo = await container.mongo;
  console.log('yolo');
  container.close();
  return;
}

const program = createProgram();
program.parse(process.argv);