将动态参数传递给函数

Question

I’ve a function which should do something like this

func getA(m *m.TSR, bl string) string {
    runParams, exist := m.BuildParams.Before[bl]
    if exist {
        runParamsMap, ok := runParams.(map[interface{}]interface{})
        if ok {
            run, ok := runParamsMap["builder"]
            if ok {
                return run.(string)
            }
        }
    }
    return ""
}


func getB(m *m.TSR, bl string) string {
    runParams, exist := m.BuildParams.After[bl]
    if exist {
        runParamsMap, ok := runParams.(map[interface{}]interface{})
        if ok {
            run, ok := runParamsMap["builder"]
            if ok {
                return run.(string)
            }
        }
    }
    return ""
}

Both function are working as expected , but I wonder if there is a way to use just only one function that handle the same ? The only difference is the Before & After

m.BuildParams.Before[bl]

m.BuildParams.After[bl]

All the reset is exactly the same, any idea how to combine them without removing the those line outside the function ….

maybe with additional parameter ....

Answer 1

One option is to move the common part to another function, e.g. get(), and change getA() and getB() to call this get():

func getB(m *m.TSR, bl string) string {
    runParams, exist := m.BuildParams.Before[bl]
    return get(runParams, exist)
}

func getB(m *m.TSR, bl string) string {
    runParams, exist := m.BuildParams.After[bl]
    return get(runParams, exist)
}

func get(runParams interface{}, exists bool) string {
    if exist {
        runParamsMap, ok := runParams.(map[interface{}]interface{})
        if ok {
            run, ok := runParamsMap["builder"]
            if ok {
                return run.(string)
            }
        }
    }
    return ""
}

If m.BuildParams.Before and m.BuildParams.After are of the same type (be it commonType), you can do better:

func getA(m *m.TSR, bl string) string {
    return get(m.BuildParams.Before, bl)
}

func getB(m *m.TSR, bl string) string {
    return get(m.BuildParams.After, bl)
}

And only the first line changes in get():

func get(common commonType, bl string) string {
    runParams, exist := common[bl]
    // rest is same
}