@sedlak.r/mq v1.1.0

EventEmitter

Info

Message queue for events. Is used for sending events, requests, notify information and binding events on dom elements. It is a minimalistic library (< 8kB min file) and is really simple to use it.

How to install

Download and install NodeJs

Run command npm install

How to release

• install
• commit changes
• bump version in package json
• run grunt default task
• run npm publish in root directory

Test status on CodeShip

CodeShip Continuous integration project

Methods

.create(context)

It's method for creating new emitter with given context. Context can be any object od any function. It is use for manipulation with handlers. More information in section "How to use it"

.event(name, params)

Call event with given name and send through given params. This function is call immediately after you call it.

.notify(name, params)

Call notify with given name and send through given params. This function is same like .event() but it can be called after same time. It's only notifier and you cannot determine when it's called, because there can be timeout due to other events, requests or notify.

.request(name, params)

Call request with given name and send through given params and get return from this call. This is similar to .event() but this function return value. This is a really special method and EventEmitter check if it's right called. If .request() has not any handler, than fail because without handler you can not get return value. Call also fail if there are more handlers than one, because you can not get return value from more functions.

.demand(name, params)

Call request with given name and send through given params and get return from this call. This is similar to .request() but this function return value and event return undefined. If .demand() has not any handler, than do not fail and return undefined. Call also fail if there are more handlers than one, because you can not get return value from more functions.

.subscribe()

This method is used for subscribing for events, that are triggered by .event(), .notify() or .request(). You can use it for your custom events or bind it to dom element. More information in section "How to use it"

.unsubscribe()

This method is used for stop listening for events, that are triggered by .event(), .notify() or .request(). More information in section "How to use it"

.interrupt(event, stopProp, cancelDef)

This function is used to stop browser event. There are parameters for stop propagation and cancel default action. It's helper function.

.watching(name)

This function is used for getting number of listener, who use .subscribe() method. If function return 0, nobody listen on event and is not necessary to call it.

.debugMode(state, filters)

You can turn on debug mode and filter some specific events. Other events will be writen into browser console with all parameters.

How to use it

You can use this library in global way. There is global variable EventEmitter.

Example 1

EventEmitter.subscribe("MyEvent", function (data) {
    console.log("You handler for event");
});
EventEmitter.event("MyEvent");
EventEmitter.event("MyEvent", [true, "param2"]);

In this example you can see basic usages of emitter. You can subscribe for event and call event with or without parameters. But there are two main problems. You can not destroy this handler for MyEvent, because you don't have original handler and also you don't have context, so in handler is invalid pointer on this. We can make modification for first problem.

Example 1 - first problem solve

var handler = function (data) {
  console.log("You handler for event");
};
EventEmitter.subscribe("MyEvent", handler);
EventEmitter.event("MyEvent");
EventEmitter.event("MyEvent", [true, "param2"]);
EventEmitter.unsubscribe("MyEvent", handler);

So now we can unsubscribe our event. Now we must solve the second problem. Context.

Example 1 - second problem solve

var emitter,
    context = {},
    handler = function (data) {
  console.log("You handler for event with context from 'context' variable.");
};
emitter = EventEmitter.create(context);
emitter.subscribe("MyEvent", handler);
emitter.event("MyEvent");
emitter.event("MyEvent", [true, "param2"]);
emitter.unsubscribe("MyEvent", handler);

Now we have solve second problem. This is the recommended use of EventEmitter. In every file create new instance with this as a context. If you implemented destroy on object, you can call emitter.unsubscribe() and all handlers for context will be destroyed. So we can update last example for complete clean all events.

Example 2

var emitter,
    context = {},
    handler = function (data) {
  console.log("You handler for event wit context from 'context' variable.");
};
emitter = EventEmitter.create(context);
emitter.subscribe("MyEvent", handler);
emitter.subscribe("MyEventSecond", handler);
emitter.event("MyEvent");
emitter.event("MyEvent", [true, "param2"]);
emitter.unsubscribe();

And last part is binding to DOM elements. It's easy like others thing before.

Example 3

var emitter,
    context = {},
    handler = function (data) {
  console.log("Clicked on body and destroy.");
  emitter.unsubscribe();
  //emitter.unsubscribe(document.body, "click", handler);
};
emitter = EventEmitter.create(context);
emitter.subscribe(document.body, "click", handler);

Licence

MIT License

Copyright (c) 2022 Radek Sedlák\ Copyright (c) 2015 Stanislav Hacker

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

The Software shall be used for Good, not Evil.