GeoJSON is a first class citizen in the JSAPI

[AdamMartin]

In case you missed this from the JS API team, re: GeoJSON layers:

The GeoJSON layer is a first-class citizen in the 4.x API; so just as you can style it, perform client-side queries, filter, and calculate statistics, etc – you can now enable clustering in the same way that you would with a feature layer.

https://developers.arcgis.com/javascript/latest/sample-code/featurereduction-cluster/index.htmlhttps://www.esri.com/arcgis-blog/products/product/announcements/whats-new-in-arcgis-api-for-javascri...