How to convert by javascript a layer extent from ITM (israel Tranverse Mercator) to geographic coordinate system?

[MichaelLev]

I develop on WAB. When 3D scene is displayed, then in order to goto to the extent of a feature layer which is defined on ITM coordinate system, I need to convert the layer Extent to be represented by geographis coordinate system, and I have not succeeded yet.

Help will be greatly appreciated. 

[KenBuja]

You would have to use the GeometryService project method to project this extent to a geographic coordinate system.

[MichaelLev]

Dear KenBuja, thank you!

using js api 4.* I understand I need https://developers.arcgis.com/javascript/latest/api-reference/esri-rest-geometryService.html#project

I'll try. I'll appreciate to see somce code example for e.g. Point, or on what I need now - an extent.

I am also bewildered about the "url" param of the "project" method.

Can I use the sampleserver6.arcgisonline.com or is it only for testing, and I need something else?

The web app I am developing (with WAB developer edition) is meant to run on a portal, version 10.8.1