How do I handle errors in Go when using async/await?

How do I handle errors in Go when using async/await?

In Go, you typically handle errors by checking the error return value. However, Go doesn't have built-in async/await like JavaScript. Instead, you can use goroutines and channels for concurrency.

Can you give me an example of error handling with goroutines?

Sure! You can launch a goroutine and use a channel to send errors back to the main function. Here's a simple example:

func fetchData(url string, ch chan<- error) {
    // Simulate fetching data
    if url == "" {
        ch <- fmt.Errorf("URL cannot be empty")
        return
    }
    // Assume data fetching logic here
    ch <- nil
}

func main() {
    ch := make(chan error)
    go fetchData("", ch)
    if err := <-ch; err != nil {
        fmt.Println("Error:", err)
    }
}

What if I want to wait for multiple goroutines to finish?

You can use a sync.WaitGroup to wait for multiple goroutines to complete. Here's how you can do it:

var wg sync.WaitGroup

func fetchData(url string, wg *sync.WaitGroup, ch chan<- error) {
    defer wg.Done() // Decrement the counter when the goroutine completes
    // Simulate fetching data
    if url == "" {
        ch <- fmt.Errorf("URL cannot be empty")
        return
    }
    // Assume data fetching logic here
    ch <- nil
}

func main() {
    ch := make(chan error)
    urls := []string{"http://example.com", ""}
    for _, url := range urls {
        wg.Add(1)
        go fetchData(url, &wg, ch)
    }
    go func() {
        wg.Wait()
        close(ch)
    }()
    for err := range ch {
        if err != nil {
            fmt.Println("Error:", err)
        }
    }
}