NOTE: Html.Lazy goes up to lazy8 and lazy7WithNonce, but
Html.Styled.Lazy can only go up to lazy7 and lazy6WithNonce because it
uses one of the arguments to track styling info.
Since all Elm functions are pure we have a guarantee that the same input
will always result in the same output. This module gives us tools to be lazy
about building Html that utilize this fact.
Rather than immediately applying functions to their arguments, the lazy
functions just bundle the function and arguments up for later. When diffing
the old and new virtual DOM, it checks to see if all the arguments are equal
by reference. If so, it skips calling the function!
This is a really cheap test and often makes things a lot faster, but definitely benchmark to be sure!
Same as lazy but checks on two arguments.
Same as lazy but checks on three arguments.
Same as lazy but checks on four arguments.
Same as lazy but checks on five arguments.
Same as lazy but checks on six arguments.
Same as lazy but checks on seven arguments.
Same as lazy2 but adds a nonce to the style tag.
Same as lazy3 but adds a nonce to the style tag.
Same as lazy4 but adds a nonce to the style tag.
Same as lazy5 but adds a nonce to the style tag.
Same as lazy6 but adds a nonce to the style tag.
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!