docs: add OneofValue type helper

We can't use oneof field directly. This helper allows for strict type checking and passing oneof fields as an argument Signed-off-by: clucle <[email protected]>
stephenh · Apr 18, 2024 · c61edef · c61edef
1 parent 7f36a59
commit c61edef
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/README.markdown b/README.markdown
@@ -796,6 +796,14 @@ type OneOfCase<T, K extends OneOfCases<T>> = T extends {
 }
   ? T[U]
   : never;
+
+/** Extracts the specific type of a value type from a oneOf field */
+export type OneOfValue<T, K extends OneOfCases<T>> = T extends {
+  $case: K;
+  [key: string]: unknown;
+}
+  ? T
+  : never;
 ```
 
 # Default values and unset fields