Mint
🍃
Tiny generic event emitter.
- Very simple: mint has 3 exported functions and 1 type
- Type safe: built on generics
- Fast: does not use reflection
- Independant: has no external dependencies
Get
go get github.com/btvoidx/mint
Use
// Create an emitter
e := new(mint.Emitter) // or &mint.Emmiter{}
// Create a consumer
func OnMyEvent(MyEvent) {
// do stuff with the value
}
// Subscribe
off := mint.On(e, OnMyEvent)
defer off() // don't forget to unsubsribe later!
// ...
// In some other place
mint.Emit(e, MyEvent{Msg: "Hi", FromID: 1})
mint.Emit(e, MyEvent{Msg: "Hello indeed", FromID: 2})
By importing the package as "github.com/btvoidx/mint/context" you can access contextful api.
import "github.com/btvoidx/mint/context"
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
defer cancel()
// Not all consumers may receive the message due to timeout,
// but Emit does wait for the active consumer to finish.
err := mint.Emit(e, ctx, MyEvent{Msg: "A message"})
// err is always ctx.Err()
if err != ctx.Err() { /* unreachable code */ }
Both versions can operate on the same mint.Emitter instance, as contextless api just wraps the contextful one with context.Background().
// MyEvent consumers will receive both events.
mintctx.Emit(e, ctx, MyEvent{Msg: "A message"})
mint.Emit(e, MyEvent{Msg: "A message"}) // uses context.Background()
If you prefer channel-based consumers you can create a wrapper for mint.On so that it forwards all data to a channel.
func MyOn[T any](e *mint.Emitter) (<-ch T, off func()) {
ch := make(chan T)
off := mint.On(e, func(v T) {
go func() { ch <- v }
})
return ch, func() {
off()
// drain channel so pending emits don't panic
for {
select {
case <-ch:
default:
close(ch)
return
}
}
}
}
// Use it like so
ch, off := MyOn[MyEvent](e)
defer off()
for event := range ch {
// deal with incoming data
}
For additional examples see mint_test.go.
Reporting issues
If you have questions or problems just open a new issue.
Minor Linting Corrections
Fixed some function comments and spelling mistakes. Added additional test to validate a nil-Emitter scenario.
Raised a TODO in mint.go:21/22 as the context/mint.go passes an unhandled context.Err to the main function. Currently have this handled with a throwaway.