Robert needed to fetch some details about pump configurations from the backend. The API was poorly documented, but there were other places in the code which did that, so a quick search found this block:

var getConfiguration = function(){
    ....
    var result = null;
    result = getPumpConfiguration (areaID,subStationID,mngmtUnitID,lastServiceDate,service,format,result);
    result = getPumpConfiguration (areaID,subStationID,null,lastServiceDate,null,format,result);
    result = getPumpConfiguration (areaID,subStationID,null,lastServiceDate,service,null,result);
    result = getPumpConfiguration (areaID,subStationID,mngmtUnitID,lastServiceDate,null,null,result);
    result = getPumpConfiguration (areaID,subStationID,null,lastServiceDate,null,null,result);
    return result;
}

This collection of lines lurked at the end of a 100+ line function, which did a dozen other things. At a glance, it’s mildly perplexing. I can see that result gets passed into the function multiple times, so perhaps this is an attempt at a fluent API? So this series of calls awkwardly fetches the data that’s required? The parameters vary a little with every call, so that must be it, right?

Let’s check the implementation of getPumpConfiguration…

function getPumpConfiguration (areaID,subStationID,mngmtUnitID,lastServiceDate,service,format,result) {
    if (result==null) {
    ...
    result = queryResult;
    ...
    }
    return result;
}

Oh, no. If the result parameter has a value… we just return it. Otherwise, we attempt to fetch data. This isn’t a fluent API which loads multiple pieces of data with separate requests, it’s an attempt at implementing retries. Hopefully one of those calls works.