event-state
v1.0.0
Published
simple event based state machine for js, written mostly for monument and action
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event-state
A state machine for events.
API
var Emitter = require('events').EventEmitter, //Any event emitter will do.
emitter = new Emitter(),
state;
// Event State extends your chosen event emitter.
emitter.required = require('event-state');
// `required` returns a state object with `add` and `clear` methods.
state = emitter.required(['event-one', 'event-two'], function (dataArray) {
//this function will be executed when all of the
// required events are triggered.
}, scope);
// The `add` method will dynamically add events to your event state machine.
// Multiple events can be added either as an arguments list or an array of events.
state.add('event-three');
state.add('event-three', 'event-four');
state.add(['event-five', 'event-six']);
// `cancel` will remove all events from your state machine.
state.cancel();
Very simple and concise. Collects a list of events, and when all the events have been triggered it executes the callback passing it an array containing the data received by each event in the order in which they were added.
dataArray
is in the order in which the events are declared in the required events array and the order in which they were added via the add
method.
scope
is the scope that will be applied to the callback function.
required
needs to be attached to an event emitter that has an on
, one
or once
function that listens to events. It uses one of them (once > one > on) to do it's listening. on
is less then ideal and most likely will cause a memory leak of some sort.
required
returns an object with add
and cancel
methods.
The add
method dynamically adds events to the state machine. The required callback will only fire once the event-state machine has "heard" all events registered with it.
The cancel
method will immediately clear the event-state machine of all events.
Returns
state
above is an object that contains a cancel
and add
function respectively.
state.add(event-name-in)
adds that event or events to your required state. This is handy for lots of stuff... ok like one thing: building file structure into an object.
state.cancel()
let's you cancel the entire thing. That way if you are waiting on event-a, event-b and event-x but want to bail on the operation if event-x and event-y are triggered then you just call state.cancel() and are done with it.