Note: This plugin was removed from GSAP 3. However, you can register this unofficial plugin to get the effect back.
Tweens any rotation-related property to another value in a particular direction which can be either clockwise ("_cw" suffix), counter-clockwise ("_ccw" suffix), or in the shortest direction ("_short" suffix) in which case the plugin chooses the direction for you based on the shortest path. For example:
//obj.rotation starts at 45
var obj = {rotation:45};
// In GSAP 3 directionalRotation is built in):
//tweens to the 270 position in a clockwise direction
gsap.to(obj, {duration: 1, directionalRotation: {rotation: "270_cw"}});
//tweens to the 270 position in a counter-clockwise direction
gsap.to(obj, {duration: 1, directionalRotation: {rotation: "270_ccw"}});
//tweens to the 270 position in the shortest direction (which, in this case, is counter-clockwise)
gsap.to(obj, {duration: 1, directionalRotation: {rotation:"270_short"}});
// In GSAP 2 (directionRotation is an external plugin):
//tweens to the 270 position in a clockwise direction
TweenLite.to(obj, 1, {directionalRotation:"270_cw"});
//tweens to the 270 position in a counter-clockwise direction
TweenLite.to(obj, 1, {directionalRotation:"270_ccw"});
//tweens to the 270 position in the shortest direction (which, in this case, is counter-clockwise)
TweenLite.to(obj, 1, {directionalRotation:"270_short"});
We used rotation here but it could be anything, like newRot.x. Notice that the value is in quotes, thus a string with a particular suffix indicating the direction ("_cw", "_ccw", or "_short"). You can also use the "+=" or "-=" prefix to indicate relative values.