kataras/go-events

Simple EventEmmiter for Go Programming Language. Inspired by Nodejs EventEmitter. For Generics support please wait until go1.18 stable is released, until then switch to dev branch instead.

Overview

New() EventEmmiter // New returns a new, empty, EventEmmiter

// AddListener is an alias for .On(eventName, listener).
AddListener(EventName, ...Listener)
// Emit fires a particular event,
// Synchronously calls each of the listeners registered for the event named
// eventName, in the order they were registered,
// passing the supplied arguments to each.
Emit(EventName, ...interface{})
// EventNames returns an array listing the events for which the emitter has registered listeners.
// The values in the array will be strings.
EventNames() []EventName
// GetMaxListeners returns the max listeners for this emmiter
// see SetMaxListeners
GetMaxListeners() int
// ListenerCount returns the length of all registered listeners to a particular event
ListenerCount(EventName) int
// Listeners returns a copy of the array of listeners for the event named eventName.
Listeners(EventName) []Listener
// On registers a particular listener for an event, func receiver parameter(s) is/are optional
On(EventName, ...Listener)
// Once adds a one time listener function for the event named eventName.
// The next time eventName is triggered, this listener is removed and then invoked.
Once(EventName, ...Listener)
// RemoveAllListeners removes all listeners, or those of the specified eventName.
// Note that it will remove the event itself.
// Returns an indicator if event and listeners were found before the remove.
RemoveAllListeners(EventName) bool
// Clear removes all events and all listeners, restores Events to an empty value
Clear()
// SetMaxListeners obviously this function allows the MaxListeners
// to be decrease or increase. Set to zero for unlimited
SetMaxListeners(int)
// Len returns the length of all registered events
Len() int

import "github.com/kataras/go-events"

// initialize a new EventEmmiter to use
e := events.New()

// register an event with name "my_event" and one listener
e.On("my_event", func(payload ...interface{}) {
  message := payload[0].(string)
  print(message) // prints "this is my payload"
})

// fire the 'my_event' event
e.Emit("my_event", "this is my payload")

Default/global EventEmmiter

// register an event with name "my_event" and one listener to the global(package level) default EventEmmiter
events.On("my_event", func(payload ...interface{}) {
  message := payload[0].(string)
  print(message) // prints "this is my payload"
})

// fire the 'my_event' event
events.Emit("my_event", "this is my payload")

Remove an event

events.On("my_event", func(payload ...interface{}) {
  // first listener...
},func (payload ...interface{}){
  // second listener...
})

println(events.Len()) // prints 1
println(events.ListenerCount("my_event")) // prints 2

// Remove our event, when/if we don't need this or we want to clear all of its listeners
events.RemoveAllListeners("my_event")

println(events.Len()) // prints 0
println(events.ListenerCount("my_event")) // prints 0

Installation

The only requirement is the Go Programming Language.

$ go get -u github.com/kataras/go-events

FAQ

Explore these questions or navigate to the [community chat][Chat].

Versioning

Current: v0.0.3

Read more about Semantic Versioning 2.0.0

• http://semver.org/
• https://en.wikipedia.org/wiki/Software_versioning
• https://wiki.debian.org/UpstreamGuide#Releases_and_Versions

Contributing

If you are interested in contributing to the go-events project, please prepare a PR.

License

This project is licensed under the MIT License.

License can be found here.