First, register a KJS block entity casually:...

 StartuPEVENTS.Registry ("block", event => {

Event.create ("test_block", "basic")
.BlockIntity (BlockentityInfo => {{
Blockityinfo.enablesync () // Important, setting can synchronize data
}) LightLevel (15)
}) 

Register rendering: startup.

 global.inited = false

Clientevents.init (event => {{
Global.inited = true
Event.registerBlockIntityRenderer ("Kubejs: test_block", (context) => renderjsblocklyrenderererererer
.Create (context)
.Setcustomrender (Renderer, Context) => {
Var posstack = context.posestack
Var light = levelrenderer.getlightColor (context.blockentityjs.level, context.blockntityjs.blockpos.above ()) // Get the brightness
Var item = item.empty
Var data = context.blockntityjs.data//
If (data.contains ("item") {{
Item = item.of (data.getstring ("item"))
}
Ifm! = Item.empty) {
PoseStack.pushpose ()
PoseStack.translaate (0.5, 1.5, 0.5) // Translation (0.5, 1.5, 0.5)
PoseStack.mulpose (VEC3F.XN.rotationDegrees (90)) // X -axis rotation 90 degrees
Renderer.ItemRenderer.RendersStatic (item, "group", light, context.packedoverlay, context.posestack, context.buffersource, client.player.Getid ()))
PoseStack.poppose ()
}
PoseStack.pushpose ()
PoseStack.translate (0.25, 1, 0.25)
Posestack.scale (0.5, 0.5, 0.5)
Renderer.BlockRenderDispatcher.RendersingleBlock (blocks.fire.defaultBlockstate (), context.posestack, context.buffersource, light, context.pack Edoverlay)
PoseStack.poppose ()})
Cure
}) 

Right -click event: server.

 const $ blockersityjs = java.loadClass ("dev.latvian.mods.block.entity.blockntityjs")

Blockevents.richtclicked (event => {{
Var block = event.getBlock ()
Var entity = block.entity
If (entity instanceof $ Blockntityjs) {
Entity.data.putString ("item", event.player.getmainhanditem (). Getid ()))
Console.log (Entity.data);
Entity.sync () // Manual synchronization
}
}) 

What? I hope to adjust in the game? (Client script)

 if (global.inited) {

Var renderr = Client.getBlockIntityRenderspatcher (). RJS $ GetRendererByType ("Kubejs: Test_block") // Get Render
If (Renderer InstanceOf RenderJSBLOCKENTITYRENDERERERERER) {
// Reset the render
Renderer.setCustomrender (Renderer, Context) => {
Var posstack = context.posestack
Var light = levelrenderer.getlightColor (context.blocktityjs.level, context.blocktityjs.blockpos.above ())))))))))))))))
Var item = item.empty var data = context.blocktityjs.data
If (data.contains ("item") {{
Item = item.of (data.getstring ("item"))
}
Ifm! = Item.empty) {
PoseStack.pushpose ()
PoseStack.translate (0.5, 1.5, 0.5)
Posestack.mulpose (VEC3F.XN.rotationDegrees (90))
Renderer.ItemRenderer.RendersStatic (item, "group", light, context.packedoverlay, context.posestack, context.buffersource, client.player.Getid ()))
PoseStack.poppose ()
}
PoseStack.pushpose ()
PoseStack.translaate (0.25, 1, 0.25) posestack.scale (0.5, 0.5, 0.5)
Renderer.BlockRenderDispatcher.RendersingleBlock (blocks.fire.defaultBlockstate (), context.posestack, context.buffersource, light, context.pack Edoverlay)
PoseStack.poppose ()
})
}
} 

Just set the RELOAD Client.

Effect:

When right -clicking, the items on your hand will be displayed.