Attribute expression in custom extension not working

[master_t]

Hi everyone

I'm writing a Visualization Extension for QlikSense, and I'm trying to add a custom expression to a measure so it will be evaluated for each row. As a guide, I'm using the example from the accepted answer here: Qliksense custom measure property for extension with expression value

Here's my definition:

definition : {
    type : "items",
    component : "accordion",
    items : {
        dimensions : {
            uses : "dimensions",
            min : 1
        },
        measures : {
            uses : "measures",
            min : 1,
            items: {
                VisibilityExpressionProperty : {
                    type: "string",
                    label: "Column visibility condition",
                    ref: "qAttributeExpressions.0.qExpression",
                    component: 'expression',
                    defaultValue: ""
                }
            }
        },
        sorting : {
            uses : "sorting"
        },
        settings : {
            uses : "settings",
            items : {
                initFetchRows : {
                    ref : "qHyperCubeDef.qInitialDataFetch.0.qHeight",
                    label : "Initial fetch rows",
                    type : "number",
                    defaultValue : 50
                }
            }
        }
    }
}

In the example I linked above, the author says that this should result in having the expression available in the hypercube, like this:

qHypercube.qDataPages[0].qMatrix.qAttrExps

However, this is not the case. As you can see, my matrix only contains the objects, but not the extra attribute:

Can anyone tell me why?

Also, is this stuff documented anywhere in the official documentation? I only found it by google searching....

[master_t · Accepted solution]

Solved it.

Apparently, the attribute only gets added if the value is not null. I thought that setting defaultValue: ""  would give me an empty string, but apparently not, its treated as NULL.