equivalent of app.controls.tween easing

so we are moving a camera via app.controls.tween (copied from tweenCamera puzzle)

but we want to match the camera movement with another animation, that runs at the same time, with the same easing applied.

from tweenjs, both quadInOut and sineInOut seem to be a close match, but are still a bit different, and make it look a bit odd, because the camera temporarily leaps ahead / lacks behind.

so it would be helpful to know what the easing function used in app.controls.tween is, so we can match it with our own animation.