container.js

'use strict';

/**
 * =============================================================================================
 * A state container
 * @exports {Object} Continer
 *
 * // in the very beginning
 * const con = require('container.js')
 * con.add('logger', new Logger('log'));
 * con.add('debug', new Logger('debug'));
 *
 * // some other place
 * const con = require('container.js')
 * const logger = con.get('logger');
 * const debug = con.get('debug');
 * =============================================================================================
 */

const is = require('is_js');
const emit = require('./emitter');

function emitError(type, error, data = {}) {
  emit.error('container', type, error, data);
}

class Container {
  /**
   * @param {Object} data -> intialize with this data
   */
  constructor(data) {
    this.data = Object.assign({}, data);
    this.IOC = Container;
  }

  /**
   * It won't rewrite if the key already exists, use update
   */
  add(key, value) {
    if (is.not.undefined(this.data[key])) {
      const error = new Error(`Can't add <${key}>, already existing`);
      emitError('key', error, {
        key,
      });
      throw error;
    }
    this.data = Object.assign(this.data, {
      [key]: value,
    });
  }

  get(key, silent) {
    const value = this.data[key];
    if (!silent && is.undefined(value)) {
      const error = new Error(`No key <${key}> found`);
      emitError('key', error, {
        key,
      });
      throw error;
    }
    return value;
  }

  /**
   * This will add or update
   */
  set(key, value) {
    this.data = Object.assign(this.data, {
      [key]: value,
    });
  }

  /**
   * Unpack, just expose the data object
   */
  unpack() {
    return this.data;
  }
}

module.exports = new Container();