core/events.js

/*
 * Your installation or use of this SugarCRM file is subject to the applicable
 * terms available at
 * http://support.sugarcrm.com/Resources/Master_Subscription_Agreements/.
 * If you do not agree to all of the applicable terms or do not have the
 * authority to bind the entity as an authorized representative, then do not
 * install or use this SugarCRM file.
 *
 * Copyright (C) SugarCRM Inc. All rights reserved.
 */
/**
 * Events proxy object.
 * For inter-component communications, please register your events and please
 * subscribe to your events from the events hub. This reduces coupling between
 * components.
 *
 * Usage example:
 * ```
 * const Events = require('core/Events');
 * var foo = {
 *     initialize: function() {
 *         // Register the event with the events hub.
 *         Events.register('mynamespaced:event', this);
 *     },
 *     action: function() {
 *         // Broadcast your event to the events hub.
 *         // The events hub will then broadcast this event to all its subscribers.
 *         this.trigger('mynamespaced:event');
 *     }
 * }
 *
 * var bar = {
 *     initialize: function() {
 *         // Call a callback when the event is received.
 *         Events.on('mynamespaced:event', function() {
 *             alert('Event!');
 *         });
 *     }
 * }
 *```
 * @module Core/Events
 */

/**
 * List of deprecated events. A warning will be shown in console when a
 * component is listening to them.
 *
 * @property {Object} _deprecated
 * @property {string} [_deprecated.message] The custom deprecation message.
 * @private
 */
let _deprecated = {};

/**
 * @alias module:Core/Events
 */
const Events = _.extend({}, Backbone.Events, {

    /**
     * Registers an event with the event proxy.
     *
     * @param {string} event The name of the event.
     *   A good practice is to namespace your events with a colon.
     *   For example: `app:start`.
     * @param {Object} context The object that will trigger the event.
     * @param {Object} [options] Optional params.
     * @param {boolean} [options.deprecated=false] `true` if the event is
     *   deprecated.
     * @param {string} [options.message] The deprecation message to log. A
     *   default message will be triggered if not defined.
     */
    register: function (event, context, options) {
        if (options && options.deprecated) {
            _deprecated[event] = _.pick(options, 'message');
        }

        context.on(event, function() {
            var args = [].slice.call(arguments, 0);
            args.unshift(event);
            this.trigger.apply(this, args);
        }, this);
    },

    /**
     * Unregisters an event from the event proxy.
     *
     * @param {Object} context Source to be cleared from.
     * @param {string} [event] Name of the event to be cleared. If not
     *   specified, all events registered on `context` will be cleared.
     */
    unregister: function(context, event) {
        context.off(event);
    },

    /**
     * Subscribes to global ajax events.
     */
    registerAjaxEvents: function() {
        var self = this;

        // First unbind then rebind
        $(document).off("ajaxStop");
        $(document).off("ajaxStart");

        $(document).on("ajaxStart", function(args) {
            self.trigger("ajaxStart", args);
        });

        $(document).on("ajaxStop", function(args) {
            self.trigger("ajaxStop", args);
        });
    },

    /**
     * Wraps [Backbone.Events#on](http://backbonejs.org/#Events-on)
     * to throw a warning if the event listened to is deprecated.
     *
     * @function
     */
    on: _.wrap(Backbone.Events.on, function (fn, name, callback, context) {

        if (_.has(_deprecated, name)) {
            var warnMessage;
            if (_deprecated[name].message) {
                warnMessage = _deprecated[name].message;
            } else {
                warnMessage = 'The global event `' + name + '` is deprecated.';
            }

            if (context) {
                warnMessage += '\n' + context + ' should not listen to it anymore.';
            }

            SUGAR.App.logger.warn(warnMessage);
        }

        return fn.call(this, name, callback, context);
    }),
});

module.exports = Events;