semi-related: is there any notable usability research on full screen search forms?
Depends on the use case.
If the user searches something already available in the current page you should use a simple input.
If the user goes to the search box because the current page doesn't have what he wants, the full screen search makes total sense. You offer him a focused view where he can try different inputs and decide between recommendations.
Visually very cool effects! All are very contingent on the use case. And really in most cases I feel they are excessive, and overly elaborate. The effect is removing the user from the context of the interface that they are searching. Why not simply live filter the content below instead of completely removing the existing interface when searching?
Really smooth, Pedro! Kudos Some of these flow really well on a mobile form factor.
Last one. ✌️