Doesn't return JSON when using goroutine?

Question

go

Good afternoon. Tell me, I can’t get an error in JSON if I send all the construction
code to a single goroutine for processing

func() {
    err := add_user(name,pass)
    if err != nil {
        jsresponce, _ := json.Marshal(Error{"   User "+name+" is already exist  !!!!  "})
        io.WriteString(w, string(jsresponce))
        return
    }
}()

so it returns an error in the JSON string
if run as

go func() {
    err := add_user(name,pass)
    if err != nil {
        jsresponce, _ := json.Marshal(Error{"   User "+name+" is already exist  !!!!  "})
        io.WriteString(w, string(jsresponce))
        return
    }
}()

it does not return, can you tell me what the problem is?

Answer 1

Because you don't wait for the goroutine to complete, you exit the json_directory function before the goroutine finishes running. Accordingly, you do not have time to see the result.
In your situation, I don’t see the point of putting it in a goroutine at all. You still have to wait for completion to show the answer, so you can just leave it as the first option.