Names reaching this function often come from data the type system never saw —
a scene file (§79), an editor field, a string built at runtime — so an
unknown name throws FourError("INVALID_APPLICATION_STATE") rather than
returning undefined and animating with undefined later, far from the
mistake. Inherited properties ("toString", "constructor") are rejected
the same way: only own keys of EASINGS resolve.
Resolves an easing name to its function.
Names reaching this function often come from data the type system never saw — a scene file (§79), an editor field, a string built at runtime — so an unknown name throws
FourError("INVALID_APPLICATION_STATE")rather than returningundefinedand animating withundefinedlater, far from the mistake. Inherited properties ("toString","constructor") are rejected the same way: only own keys of EASINGS resolve.