How to select the date of most recent record in featurelayer to automatically configure time slider

EmilyGoldsmith

Hello,

I'm in a bit of an tricky situation where a layer with automatic refreshes in one of our ArcGIS JavaScript apps  has been configured to have an incorrect, static time extent in its timeinfo - with us being unable to make changes to said layer currently. This has led our time slider to have the wrong time extent info in our ArcGIS JavaScript 4.27 app.

A quick fix I came up with was to overwrite the time extent when setting up the timeslider, which has fixed the time extent issue temporarily - see here:

 

//create time slider for layer 
        const timeSlider = new TimeSlider({
        container: "timeSlider",
        view: view,
        timeVisible: true, // show the time stamps on the timeslider
        loop: true,
        fullTimeExtent: { // entire extent of the timeSlider
          start: new Date(2003, 5, 19),
          end: new Date(2024, 5, 16)
  },
        });
      
        view.whenLayerView(layer).then((lv) => {timeSlider.fullTimeExtent.expandTo("weeks");
        timeSlider.stops = {interval: layer.timeInfo.interval};
        });

        view.ui.add(timeSlider, "bottom-left");

 

However, I would like to have a way to automatically get the most recent date from the feature layer's time field 'DATE_CREATED' and have this set to be the 'end' value in TimeSlider()'s 'fullTimeExtent.'

Does anybody know if this is possible?

Thank you.

EmilyGoldsmith

Hi, just to give an update on this but I think I figured out how to do it by adding a statistical query to your code.

Essentially, the following queries by the 'maximum' date in the FeatureLayer and then selects this date to be the timeslider's new 'enddate.'

 

//Get the 'maximum' date (most recent)   
 const query = new Query();
    query.outStatistics = [{
  onStatisticField: "DATE_CREATED",
  outStatisticFieldName: "MAX_DATE",
  statisticType: "max"
  }];
  
//Query by the maxmimum date query set above
layer.queryFeatures(query).then((featureSet) => {
  
  const endDateAttribute = featureSet.features[0].attributes.MAX_DATE;
  console.log("Most Recent Date", endDateAttribute); //Print this date

       // Create a Date object from the attribute value
       const enddate = new Date(endDateAttribute);
              console.log("enddate" , {enddate}); //Ensure date converted successfully
          
  //create time slider for layer 
  const timeSlider = new TimeSlider({
  container: "timeSlider",
  view: view,
  timeVisible: true, // show the time stamps on the timeslider
  loop: true,
  fullTimeExtent: { // entire extent of the timeSlider
    start: new Date(2003, 5, 19),
    end: enddate}
  });

  view.whenLayerView(layer).then((lv) => {timeSlider.fullTimeExtent.expandTo("weeks");
  timeSlider.stops = {interval: layer.timeInfo.interval};
  });
  view.ui.add(timeSlider, "bottom-left"); 
});

 

A solution to why the code in my previous message didn't work is because QueryTasks have a limit of 1000 (see here.) Reading this post,  I was concerned I might have had to query by the maximum OBJECTID but this solution seems to work surprisingly well for now. Though I will keep an eye on it to ensure that it functions as it should. 

Thanks again for your help!