spark.js

    const cam = Camera.worldTransform.position;
    var subscription =
        Reactive
            .monitorMany(
                {
                  // Monitor camera position, this needs to be done per component since they are individual signals
                  cx: cam.x,
                  cy: cam.y,
                  cz: cam.z,
                  ox: sparkObject.transform.position.x,
                  oy: sparkObject.transform.position.y,
                  oz: sparkObject.transform.position.z,
                  // Monitor world tranform for parent changes.
                  wx: sparkObject.worldTransform.position.x,
                  wy: sparkObject.worldTransform.position.y,
                  wz: sparkObject.worldTransform.position.z,
                },
                {fireOnInitialValue: true})
            .subscribe((changes) => {
              var cameraPos = {
                x: changes.newValues.cx,
                y: changes.newValues.cy,
                z: changes.newValues.cz
              };
              var objPos = {
                x: changes.newValues.ox,
                y: changes.newValues.oy,
                z: changes.newValues.oz
              };
              var driver =
                  Animation.timeDriver({durationMilliseconds: 1, loopCount: 1});
              sparkObject.transform.x = Animation.animate(
                  driver,
                  Animation.samplers.linear(objPos.x, changes.newValues.cx))
              driver.start();
            });