Are these line codes the same in golang?-CodePudding

Is A same as B?

if err := json.NewDecoder(r.Body).Decode(&t); err != nil {
    rnd.JSON(w, http.StatusProcessing, err)
    return
}

err := json.NewDecoder(r.Body).Decode(&t);
if err != nil {
    rnd.JSON(w, http.StatusProcessing, err)
    return
}

CodePudding user response：

They are equivalent except one difference: the scope of the err variable. In the A version the scope of the err variable is the if statement: it's not accessible after the if.

In the B version the err variable will be in scope after the if statement too, and if err is already defined earlier, it could result in a compile-time error too.

It's good practice to always minimize the scope of variables (which gives you less chance to misuse them). If you do not wish to further examine the returned error after the if, it's better to use the A version. If you do need it after the if, then obviously the B version is the way to go.