有没有办法在链式调用中传播变量的“零”？

I have the following in Go:

checkItemState := action.Data.CheckItem.State
if checkItemState != "" {
            fmt.Printf("checklist item state: %s", action.Data.CheckItem.State)
}

Now if any of the items in the chain action.Data.CheckItem are nil/empty, I get a nil pointer dereference error, which makes sense.

But is there a language level way to get checkItemState if not nil, or "" if any of the items in the chain are nil/empty.

(I come from Obj-C/Swift land where the nilness propagates)

You can handle this nicely if you code some getters. Go method receivers are just regular function arguments, so it's totally ok to call something on a nil receiver:

type Foo struct {
    Name string
}

func (f *Foo) GetName() string {
    if f == nil {
        return "default name" // or "", whatever
    }
    return f.Name
}

https://play.golang.org/p/Q20lSo65Kx

This trick is used e.g. by Go protobuf implementation.