partof-webxr-lefttrigger-motioncontroller-bjs.js

   xr.input.onControllerAddedObservable.add((controller) => {
       controller.onMotionControllerInitObservable.add((motionController) => {
           if (motionController.handness === 'left') {
                const xr_ids = motionController.getComponentIds();
                let triggerComponent = motionController.getComponent(xr_ids[0]);//xr-standard-trigger
                triggerComponent.onButtonStateChangedObservable.add(() => {
                    if (triggerComponent.pressed) {
                        Box_Left_Trigger.scaling= new BABYLON.Vector3(1.2,1.2,1.2);
                    
                    }else{
                        Box_Left_Trigger.scaling= new BABYLON.Vector3(1,1,1);
                    
                    }
                });