Event

A small, generic, in-process event emitter for Go. Inspired by Laravel's simple take on the observer pattern.

Installation

$ go get github.com/gocrumb/event

Requires Go 1.21+.

Usage

Declare an event type and a typed emitter for it:

package main

import (
	"context"
	"fmt"

	"github.com/gocrumb/event"
)

type OrderPlaced struct {
	OrderID    int
	CustomerID int
}

var OrderPlacedEvent event.Emitter[OrderPlaced]

Register handlers:

OrderPlacedEvent.HandleFunc(func(ctx context.Context, e OrderPlaced) {
	fmt.Println("New Order")
	fmt.Println("Order ID:   ", e.OrderID)
	fmt.Println("Customer ID:", e.CustomerID)
})

Trigger the event from elsewhere in your application:

OrderPlacedEvent.Trigger(ctx, OrderPlaced{
	OrderID:    5,
	CustomerID: 265,
})

The zero value of Emitter is ready to use. Handlers run synchronously, in registration order, on the goroutine that calls Trigger.

Documentation

• Reference

Contributing

Contributions are welcome.

License

This package is available under the BSD (3-Clause) License.