publisher-subscriber-pattern/dist/publisher.js

Publisher subscriber pattern that can be used with different event emitters including browser window

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.Publisher = void 0;

var _types = require("./_types");

var _subscriber = require("./subscriber");

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }

function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); return Constructor; }

function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }

var Publisher =
/*#__PURE__*/
function () {
  function Publisher() {
    var _this = this;

    _classCallCheck(this, Publisher);

    _defineProperty(this, "eventData", void 0);

    _defineProperty(this, "addEventListener", void 0);

    _defineProperty(this, "removeEventListener", void 0);

    _defineProperty(this, "subscribe", function (eventName, eventCallback, subscriberInstance) {
      var subscriber = new _subscriber.Subscriber(eventCallback, subscriberInstance);

      var eventData = _this.getEventData(eventName);

      if (!eventData) {
        eventData = _this.eventData.set(eventName, [_this.buildInformSubscribers(eventName), []]).get(eventName);

        _this.observeEvent(eventName, eventData);
      }

      eventData[1].push(subscriber);
      return _this.unsubscribe(eventName, subscriber);
    });

    _defineProperty(this, "unsubscribeAll", function () {
      Array.from(_this.eventData.keys()).forEach(function (eventName) {
        _this.unobserveEvent(eventName);
      });
    });

    _defineProperty(this, "eventSubscribersCount", function (eventName) {
      return (_this.getSubscribers(eventName) || []).length;
    });

    _defineProperty(this, "subscribersCount", function () {
      return Array.from(_this.eventData.values()).reduce(function () {
        var count = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 0;
        var eventData = arguments.length > 1 ? arguments[1] : undefined;
        count += eventData[1].length;
        return count;
      }, 0);
    });

    _defineProperty(this, "buildInformSubscribers", function (eventName) {
      return function (event) {
        (_this.getSubscribers(eventName) || []).forEach(function (subscriber) {
          return subscriber.eventCallback(event);
        });
      };
    });

    _defineProperty(this, "unsubscribe", function (eventName, subscriber) {
      return function () {
        var subscribersArray = (_this.getEventData(eventName) || [])[1];

        if (subscribersArray) {
          subscribersArray.splice(subscribersArray.findIndex(function (item) {
            return item === subscriber;
          }), 1);

          if (!subscribersArray.length) {
            _this.unobserveEvent(eventName);
          }
        }

        return;
      };
    });

    _defineProperty(this, "observeEvent", function (eventName, eventData) {
      var eventCallback = eventData ? eventData[0] : _this.getEventCallback(eventName);

      if (eventCallback) {
        _this.addEventListener(eventName, eventCallback);
      }
    });

    _defineProperty(this, "unobserveEvent", function (eventName) {
      _this.removeEventListener(eventName, _this.getEventCallback(eventName));

      _this.eventData["delete"](eventName);
    });

    for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
      args[_key] = arguments[_key];
    }

    var emitterInstance = args[0],
        addListenerMethodName = args[1],
        removeListenerMethodName = args[2];

    if (!(0, _types.isValidEmitter)(emitterInstance, addListenerMethodName, removeListenerMethodName)) {
      throw new Error('Publisher received incorrect arguments');
    }

    this.eventData = new Map([]);
    this.addEventListener = // @ts-ignore
    emitterInstance[addListenerMethodName].bind(emitterInstance);
    this.removeEventListener = // @ts-ignore
    emitterInstance[removeListenerMethodName].bind(emitterInstance);
  }

  _createClass(Publisher, [{
    key: "getEventData",
    value: function getEventData(eventName) {
      return this.eventData.get(eventName);
    }
  }, {
    key: "getEventCallback",
    value: function getEventCallback(eventName) {
      return (this.getEventData(eventName) || [])[0];
    }
  }, {
    key: "getSubscribers",
    value: function getSubscribers(eventName) {
      return (this.getEventData(eventName) || [])[1];
    }
  }]);

  return Publisher;
}();

exports.Publisher = Publisher;