Add tip for recursively dereferencing registry schemas

docs/tips.md

@@ -539,3 +539,33 @@ Example utility to convert schemas recursively:
 ;                [:int {:gen/elements [1 2 3]}]
 ;                :string]]]]]
 ```
+
+## De-reference schemas from a registry
+
+When transforming schemas, if they are provided by a registry, it's useful to dereference them first.
+
+```clojure
+(defn deref-recursive
+  "deref all schemas at all levels so the resulting schema has no registry references"
+  [schema]
+  (m/walk schema
+          (m/schema-walker m/deref-all)
+          {::m/walk-schema-refs true
+           ::m/walk-refs        true}))
+
+(def smart-phone
+  (m/schema "smart-phone"
+            {:registry (merge (m/default-schemas)
+                              {"smart-phone" [:map
+                                              [:type [:enum :android :iphone]]
+                                              [:connector "connector"]]
+                               "connector"   [:enum :usb-c :micro-usb :lightning]})}))
+
+(deref-recursive smart-phone)
+=> [:map 
+    [:type [:enum :android :iphone]] 
+    [:connector [:enum :usb-c :micro-usb :lightning]]]
+```
+
+The fully de-referenced schema is plain data which is much easier to transform. 
+