Golang notes

ch := make(chan int)
go func() {
    ch <- 42
}()
fmt.Println(<-ch)

type Base struct {
    ID int
}

type User struct {
    Base
    Name string
}

u := User{Base: Base{ID: 1}, Name: "John"}
fmt.Println(u.ID, u.Name)

ch := make(chan int)
go func() {
    ch <- 42
}()
fmt.Println(<-ch)

Custom String Representations: • Implement the Stringer interface for custom string representations of your types

type Person struct {
    Name string
    Age  int
}

func (p Person) String() string {
    return fmt.Sprintf("%s is %d years old", p.Name, p.Age)
}

p := Person{Name: "Alice", Age: 30}
fmt.Println(p)

Use init Function for Initialization: • The init function is called before the main function and is useful for setup tasks.

var config Config

func init() {
  config = loadConfig()
}

func main() {
  fmt.Println(config)
}

func add(a, b int) int {
    return a + b
}

func TestAdd(t *testing.T) {
    result := add(2, 3)
    if result != 5 {
        t.Errorf("expected 5, got %d", result)
    }
}

Use context for Cancellation and Timeouts: • Use the context package to handle cancellation and timeouts in concurrent operations.

func doWork(ctx context.Context) {
    select {
    case <-time.After(2 * time.Second):
        fmt.Println("Work done")
    case <-ctx.Done():
        fmt.Println("Canceled")
    }
}

func main() {
    ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
    defer cancel()
    go doWork(ctx)
    time.Sleep(2 * time.Second)
}

type Weekday int

const (
    Sunday Weekday = iota
    Monday
    Tuesday
    Wednesday
    Thursday
    Friday
    Saturday
)

func (d Weekday) String() string {
    return [...]string{"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"}[d]
}

fmt.Println(Monday) // Output: Monday