This package is part of the metaliq/ui collection of User/Human Interface mechanisms, and contains a number of standards compliant Web Components - a.k.a Custom Elements - which extend the HTML element syntax in useful ways, along with MetaViews based on these components allowing them to be easily integrated with MetaModels.
The components are:
The <animated-hide-show> element has a property called mq-hidden. When this changes, the element changes its height between zero and auto, but there is a short transition period (defined by mq-duration) during which auto is replaced by a specific value, equal to the sum of all its childrens' heights, hence giving a smooth transition.
The animatedHideShow MetaView wrapper links the mq-hidden property to the hidden term from the MetaModel.
Unlike expander, animated-hide-show retains its descendant DOM structure when hidden. This may be useful for fields such as dropdowns and date-pickers using 3rd party libraries which need to be re-instantiated when removed and added to the DOM.
The <expander> element automatically expands and contracts, with a transition on height over a given period (mq-duration), whenever its child content changes.
The expander MetaView wrapper
Whilst the behaviour of expander is automatic and unlike like animated-hide-show doesn't require a linked property, it doesn't allow for the retention of inner content during the contraction phase.