.. because we can't keep track of the model without existential types. It just eagerly evaluates. This set of function is here to serve as a drop-in replacement.
Same as lazy but checks on two arguments.
Same as lazy but checks on three arguments.
A performance optimization that delays the building of virtual DOM nodes.
Calling
(view model)will definitely build some virtual DOM, perhaps a lot of it. Calling(lazy view model)delays the call until later. During diffing, we can check to see ifmodelis referentially equal to the previous value used, and if so, we just stop. No need to build up the tree structure and diff it, we know if the input toviewis the same, the output must be the same!