initialProperties specifies the properties of your visualization or extension object when it is first created. You can use either the qHyperCubeDef or qListObjectDef, which will be elaborated on later in this chapter. One example of such a property setting is as follows:

initialProperties : { 
    qHyperCubeDef : { 
        qDimensions : [], 
        qMeasures : [], 
        qInitialDataFetch : [{ 
            qWidth : 2, 
            qHeight : 50 
        }]
    }
}

Naturally, you want to leave the qDimensions and qMeasures blocks empty, as you want to give the user the ability to define those via the property panel. However, the qInitialDataFetch property can be useful to be set at this point as it defines the size of the underlying data that the extension retrieves from the Qlik Engine.

More about the qHyperCubeDef and qListObjectDef structure can be found in the course of this chapter.