Just a humble attempt to propose some addiction to the `Object.prototype` I already know many will kill me for even trying to ...
**tl;dr** - everything proposed can be already tested through this utility called [eddy.js](https://github.com/WebReflection/eddy#event-driven-js) ### Event Target All The Things One of the most widely adopted API in JavaScript world is based on a combination of these methods: * `.on(type, handler[, capture])` used as equivalent of `addEventListener` in the DOM namespace, also used in every library that would like to be event driven. Smart enough to avoid duplicated entries for the same handler over the same event type. * `.once(type, handler[, capture])` used to simplify `.on()` within an `.off()` at the top of the invocation to ensure a "one shot only" event * `.off(type, handler[, capture])` to remove a previously set event handler or silently failif not present * `.emit(type[, arg1][, argN])` directly from node.js world where almost every object is an EventTarget and EventEmitter anyhow since it's needed and has been proven it's a highly appreciated/welcome approach. * `.trigger(type[, data])` similar to `.emit()` except it triggers/fires an event object with some extra method such `evt.stopImmediatePropagation()` or others DOM related when the event comes from DOM The proposed implementation lazily assign internal listeners event handlers only once these methods are invoked for the very first time. This makes every object able to be promoted at runtime as event emitter: ```javascript var o = {}; // o is just an object o.on('event-name', console.log.bind(console)); // now o has internals able to work with handlers o.trigger('event-name'); // will log an Event object ``` ### An Extra "Should Have" Utility We talk a lot about GC these days and performance impact this has on slower device (or embedded ARM boards such R-PI or Cubieboard, hardware used in production and as server too in some crazy case!). There is a common **anti pattern** in JS code since some library introduced `Function#bind()` and ES decided to adopt it: it creates N new objects per each call. This makes it impossible to remove listeners so we are forced to address every single object. As example, back to a similar previous code example: ```javascript window.addEventListener('load', console.log.bind(console)); // now how to drop that ? ``` There is no way to remove that listener after that and developers keep passing functions, instead of objects with `handleEvent()` methods, and more complex code becomes easily messed up. `Object.prototype.boundTo(method)` would be able to solve this in a very simple way: creates, if not created already, a bound version of that method so that any further call to the same method will result in the same bound object. ```javascript window.addEventListener('load', console.boundTo(console.log)); // whenever we want to ... window.removeEventListener('load', console.boundTo(console.log)); ``` In my `eddy.js` proposal this method has a shortcut too, shortcut that might break if some obtrusive minifier as Closure Compiler with ADVANCED option is taking care of the build process. This is why I am not expecting much consensus about the overload of this `boundTo()` method but here what I've done: ```javascript window.addEventListener('load', console.boundTo('log')); // whenever we want to ... window.removeEventListener('load', console.boundTo('log')); // same as window.removeEventListener('load', console.boundTo(console.log)); ``` The method can accept either a function or a string, where in latter case, the `context[methodName]` is used to check if the bound object has been created already. `.boundTo(method)` should not accept extra arguments since in that case advantages are less than a generic bind due very exponential nature of the possible check over all arguments. In that case developers can use bind and address it if really needed but I've seen this is not the majority of the cases. **Thank You** for listening, reading, sharing thoughts, or proposing any change ... I know I'm going to be probably the only one in this planet that will pollute in a non enumerable way the `Object.prototype` with the stuff I need the most in every single piece of JS software I've written but hey ... maybe it was worth it to try to propose here too :-) Best Regards
_______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
