eventloop

Overview ¶

Package eventloop provides a thread-safe event loop for JavaScript execution.

The event loop ensures that all Goja runtime operations occur on a single goroutine, preventing race conditions. It also manages async operations through a wait group mechanism.

Basic Usage ¶

el := eventloop.NewEventLoop(vm)

el.RunOnLoop(func() {
    vm.RunString(`console.log("Hello")`)
})

el.Start() // Blocks until all work is done

Async Operations ¶

When starting an async operation (HTTP request, timer, etc.), use WGAdd to indicate pending work and WGDone when complete:

el.WGAdd(1)
go func() {
    time.Sleep(time.Second)
    el.RunOnLoop(func() {
        vm.RunString(`console.log("Delayed")`)
        el.WGDone()
    })
}()

The event loop automatically stops when all pending operations complete.

Promises ¶

CreatePromise returns a JavaScript Promise along with resolve/reject functions that properly integrate with the event loop:

promise, resolve, reject := el.CreatePromise()
go func() {
    result, err := doAsyncWork()
    if err != nil {
        reject(err)
    } else {
        resolve(result)
    }
}()
return promise