onall

This is a super simple set of helper functions that allow you to react on more complex events from an event emitter. Events can be bundled and processed when either all of them or any of them fire. There are different modes for how you want to handle repeat events.

This library is written in ECMA6 for node.js and currently not compatible with previous versions or browsers.

Installation

npm install --save onall

API

Here are some simple examples on how to use the API. For more details take a look at the test cases.

On.all()

On.all({string[]} events, {function} callback, {boolean, optional} useFirst)

React as soon as all registered events have been fired at least once (and then reset). If an event is fired before all other events are fired, the arguments are overwritten, unless useFirst is set to true in which case the first argument is used and subsequent arguments are discarded.

var On = require('onall');
var emitter = new events.EventEmitter();
var on = new On(emitter);
on.all(['event1', 'event2'], args => {
    console.log(args);
});
emitter.emit('event1', 'arg1');
emitter.emit('event1', 'arg3');
emitter.emit('event2', 'arg2');
 // => { event1: ['arg3'], event2: ['arg2'] }

On.allCached()

On.allCached({string[]} events, {function} callback, {number, optional} cacheLimit, {boolean, optional} lifo)

React as soon as all registered events have been fired at least once (and then reset). Other than the standard On.all() method this one will queue up events and not discard duplicate events. An optional limit to the size of the cache can be passed set which will discard the oldest partial entries. The limited cache can discard oldest entries first (default: lifo = false) or newest first (lifo = true).

var On = require('onall');
var emitter = new events.EventEmitter();
var on = new On(emitter);
on.allCached(['event1', 'event2'], args => {
    console.log(args);
});
emitter.emit('event1', 'arg1');
emitter.emit('event1', 'arg3');
emitter.emit('event2', 'arg2');
// => { event1: ['arg1'], event2: ['arg2'] }
emitter.emit('event2', 'arg4');
 // => { event1: ['arg3'], event2: ['arg4'] }

On.allOnce()

On.allOnce({string[]} events, {function} callback, {boolean, optional} useFirst)

Will react as soon as all events have been fired at least once and then no longer listen to events. Only the first event is recorded so that subsequent events will be ignored.

var On = require('onall');
var emitter = new events.EventEmitter();
var on = new On(emitter);
on.allOnce(['event1', 'event2'], args => {
    console.log(args);
});
emitter.emit('event1', 'arg1');
emitter.emit('event2', 'arg2');
// => { event1: ['arg1'], event2: ['arg2'] }
emitter.emit('event1', 'arg3');
emitter.emit('event2', 'arg4');
// => ignored

On.allMany()

On.allOnce({string[]} events, {number} count, {function} callback, {boolean, optional} useFirst)

Will react as soon as all events have been fired at least once and then no longer listen to events. Only the configured number of events is recorded so that subsequent events will be ignored.

var On = require('onall');
var emitter = new events.EventEmitter();
var on = new On(emitter);
on.allMany(['event1', 'event2'], 2, args => {
    console.log(args);
});
emitter.emit('event1', 'arg1');
emitter.emit('event2', 'arg2');
// => { event1: ['arg1'], event2: ['arg2'] }
emitter.emit('event1', 'arg3');
emitter.emit('event2', 'arg4');
// => { event1: ['arg3'], event2: ['arg4'] }
emitter.emit('event1', 'arg5');
emitter.emit('event2', 'arg6');
// => ignored

On.any()

On.any({string[]} events, {function} callback)

Will react as soon as any of the given events are triggered.

var On = require('onall');
var emitter = new events.EventEmitter();
var on = new On(emitter);
on.any(['event1', 'event2'], (event, arg) => {
    console.log(event, arg);
});
emitter.emit('event1', 'arg1');
=> 'event1', 'arg1'
emitter.emit('event2', 'arg2');
=> 'event2', 'arg2'

On.anyOnce()

On.anyOnce({string[]} events, {function} callback)

Will react as soon as any of the given events are triggered, and then stops listening.

var On = require('onall');
var emitter = new events.EventEmitter();
var on = new On(emitter);
on.anyOnce(['event1', 'event2'], (event, arg) => {
    console.log(event, arg);
});
emitter.emit('event1', 'arg1');
=> 'event1', 'arg1'
emitter.emit('event2', 'arg2');
=> ignored

On.anyMany()

Will react as soon as a given number of events are triggered, and then stops listening.

var On = require('onall');
var emitter = new events.EventEmitter();
var on = new On(emitter);
on.anyMany(['event1', 'event2'], 2, (event, arg) => {
    console.log(event, arg);
});
emitter.emit('event1', 'arg1');
=> 'event1', 'arg1'
emitter.emit('event2', 'arg2');
=> 'event2', 'arg2'
emitter.emit('event1', 'arg3');
=> ignored

Tests

To run the tests simply run npm test

Bugs / Feature Requests / Questions

If you have any of those you can file a ticket on Github or send me an email to [email protected]