Angular Common - utils - TransitionExecutor

While there are scenarios when animating certain elements is required, there can be more complex scenarios when you need to perform a transition - several animations of different elements performed simultaneously. For instance, when you navigate from a view to another view in a mobile application, the content of the new view replaces the content of the old view. Moreover, the header can be animated differently from the rest of the content on both views. Thus, four different animations must be performed simultaneously. To simplify the implementation of such scenarios, the TransitionExecutor is implemented.

To register the set of animations to be performed simultaneously, use the enter(elements, animation) and leave(elements, animation) methods of the TransitionExecutor object. Use the enter(elements, animation) method to specify the elements that should appear ("enter") on the page with a specified animation. The leave(elements, animation) method should be called if there are elements that must disappear ("leave") from the page.

The TransitionExecutor object is also useful when a need arises to perform a staggered animation of elements when elements are animated with a slight delay after animation of each successive element starts resulting in a curtain-like effect. In this instance, each element should be registered with by the enter(elements, animation)/leave(elements, animation) method with the animation configuration where the staggerDelay option is specified.

To start a transition, call the start() method of the TransitionExecutor object. To clear the registered set of animations in the TransitionExecutor object, call the reset() method.