Start value in Wave analytics date range widget

Question

In wave analytics dashboard I have a date range widget, which I want to be set to a date by default. Is there a way to set an initial value? In my dashboard JSON I successfully used the following snippet for a toggle:

"start": {
                "display": [
                    "Ecosystem"
                ]
            }

What about date range? I tried the following property:

"start": [[2017,3,31],[2017,4,10]]

By trial and error I found that this is the only syntax which does not throw errors but then the widget on initialization would be set to 01.01.1970. Is there any way to achieve this? I am using Trend for wave to visualize data over time and the widget is used to filter the system snapshots.

Answer 1

Found an answer! For anyone having the same problem: the correct way to do that is to use the nested array with date in milliseconds, like that:

"start": [
                [
                    1490869387000,
                    1491906187000
                ]
            ]

Answer 2

Of course, you could also set an 'Initial Selection' on the page if you wanted to do this in UI and not JSON. This is faster though because these filters are processed first by the engine.