wr-eventstore/lib/event.js

Node-eventstore is a node.js module for multiple databases. It can be very useful as eventstore if you work with (d)ddd, cqrs, eventsourcing, commands and events, etc.

var debug = require('debug')('eventstore:event'),
  _ = require('lodash');

  function put(object, path, value) {
    if (typeof path === "string") {
      path = path.split(".");
    }
  
    if (!(path instanceof Array) || path.length === 0) {
      return false;
    }
  
    path = path.slice();
  
    var key = path.shift();
  
    if (typeof object !== "object" || object === null || key === "__proto__") {
      return false;
    }
    if (path.length === 0) {
      object[key] = value;
    } else {
      if (typeof object[key] === "undefined") {
        object[key] = {};
      }
  
      if (typeof object[key] !== "object" || object[key] === null) {
        return false;
      }
  
      return put(object[key], path, value);
    }
  }

/**
 * Event constructor
 * @param {EventStream} eventstream the corresponding event stream object
 * @param {Object}      event       the event object
 * @constructor
 */
function Event (eventstream, event, eventMappings) {
  if (!eventstream) {
    var errStreamMsg = 'eventstream not injected!';
    debug(errStreamMsg);
    throw new Error(errStreamMsg);
  }

  if (!event) {
    var errEvtMsg = 'event not injected!';
    debug(errEvtMsg);
    throw new Error(errEvtMsg);
  }

  if (!eventstream.aggregateId) {
    var errAggIdMsg = 'eventstream.aggregateId not injected!';
    debug(errAggIdMsg);
    throw new Error(errAggIdMsg);
  }

  if (!_.isArray(eventstream.uncommittedEvents)) {
    var errAggIdMsg = 'eventstream.uncommittedEvents not injected!';
    debug(errAggIdMsg);
    throw new Error(errAggIdMsg);
  }

  eventMappings = eventMappings || {};

  this.streamId = eventstream.aggregateId;
  this.aggregateId = eventstream.aggregateId;
  this.aggregate = eventstream.aggregate;
  this.context = eventstream.context;
  this.streamRevision = null;
  this.commitId = null;
  this.commitSequence = null;
  this.commitStamp = null;
  this.payload = event || null;
  this.position = null;

  this.applyMappings = function applyMappings() {
    _.keys(eventMappings).forEach(function (key) {
      if (this[key] !== undefined && this[key] !== null) {
        put(this.payload, eventMappings[key], this[key]);
      }
    }.bind(this));
  };

  eventstream.uncommittedEvents.push(this);
}

module.exports = Event;