This updates cache.resolve to return undefined for uncached fields.
This has two reasons:
Resolvers allow users to return undefined to signal a cache miss, however, this wasn't clear — both because of the documentation, and because cache.resolve itself never returns undefined. Hence, while it's popular to end a resolver in a cache.resolve call, this meant that a cache miss could never be caused on this field.
Not being able to return undefined meant that the Cache interface virtually had little to no ways of actually letting a user check whether a field was cached or not. By returning undefined this now becomes clear
This isn't considered a breaking change since it shouldn't alter prior behaviour significantly:
A user may now correctly see a cache miss, where before they accidentally didn't cause one
However, manually returning null still retains the prior behaviour obviously
All methods now accept undefined, so the chainability is retained. When a method that was chainable receives undefined as its entity input, it will also typically return undefined, unless it's a write method.
Set of changes
Allow cache.resolve to return undefined
Update cache.link to better handle variable number of arguments
Allow Entity argument type in Cache to accept undefined
Update ensureLink to handle undefined values gracefully
Update docs to clarify that resolvers are allowed to return undefined
Summary
This updates
cache.resolveto returnundefinedfor uncached fields.This has two reasons:
undefinedto signal a cache miss, however, this wasn't clear — both because of the documentation, and becausecache.resolveitself never returnsundefined. Hence, while it's popular to end a resolver in acache.resolvecall, this meant that a cache miss could never be caused on this field.undefinedmeant that theCacheinterface virtually had little to no ways of actually letting a user check whether a field was cached or not. By returningundefinedthis now becomes clearThis isn't considered a breaking change since it shouldn't alter prior behaviour significantly:
nullstill retains the prior behaviour obviouslyundefined, so the chainability is retained. When a method that was chainable receivesundefinedas its entity input, it will also typically returnundefined, unless it's a write method.Set of changes
cache.resolveto returnundefinedcache.linkto better handle variable number of argumentsEntityargument type inCacheto acceptundefinedensureLinkto handleundefinedvalues gracefullyundefined