topic Re: Any subsitute for extent-change in Arcgis Javascript 4? in ArcGIS JavaScript Maps SDK Questions

Any subsitute for extent-change in Arcgis Javascript 4?

ADITYAKUMAR1 — Mon, 23 Jan 2023 18:18:36 GMT

Hi ,

I was working on Arcgis Javascript 3 with the below code.

on(this.map, "extent-change", lang.hitch(this, this.myfunction));

The above line called myfunction during load of the map .But now I am working with ArcGIS JavaScript 4. Any idea how to replicate the same in version 4?

Re: Any subsitute for extent-change in Arcgis Javascript 4?

JoelBennett — Mon, 23 Jan 2023 19:10:23 GMT

When migrating to 4.x, I found it best to replace this by watching the MapView.stationary property, in which case yours would translate to something like:

mapView.watch("stationary", this.myFunction.bind(this));

and elsewhere, something like:

myFunction: function(newValue, oldValue, propertyName, target) { if (newValue) { var extent = target.extent; //etc } }

Re: Any subsitute for extent-change in Arcgis Javascript 4?

Noah-Sager — Wed, 25 Jan 2023 14:18:04 GMT

Also, here are some good example apps related to extent changes from the SDK:

https://developers.arcgis.com/javascript/latest/sample-code/watch-for-changes-reactiveutils/

https://developers.arcgis.com/javascript/latest/sample-code/event-explorer/

https://developers.arcgis.com/javascript/latest/sample-code/watch-for-changes/

Re: Any subsitute for extent-change in Arcgis Javascript 4?

ADITYAKUMAR1 — Fri, 27 Jan 2023 16:52:51 GMT

Hi @JoelBennett , @Noah-Sager

Thanks for the response. I managed to do it in a different way.

map.View.watch("zoom", (evt) => {
if (Number.isInteger(evt)) {
this.myfunction();
}
});

Its working for now but this doesnt work when we work with custom base maps.I am not sure why it only works with default basemap gallery.

Thanks

Aditya Kumar

Re: Any subsitute for extent-change in Arcgis Javascript 4?

JoelBennett — Fri, 27 Jan 2023 17:06:27 GMT

The 3.x "extent-change" event will fire when the user pans the map, but your 4.x solution will not. Is that what you intend?

Re: Any subsitute for extent-change in Arcgis Javascript 4?

ADITYAKUMAR1 — Fri, 27 Jan 2023 17:44:46 GMT

@JoelBennett no not on extent change but on scale change Or a change in zoom level.