CodeSOD: If Not Null…

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.

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