React animate height (slide up/down) component

from blog Muffin Man, | ↗ original
Most JavaScript developers used jQuery's .slideUp() and .slideDown() methods, and got used to them. As component based frameworks usually do not include such functionality, the first logic choice is to turn to CSS. But alas, CSS transitions do not work with height: auto. (Transitions can do a tween only between two numeric values.) As we use this...