extendSchemableClass work

src/extendSchemableClass.ts

@@ -0,0 +1,79 @@
+import { AbstractClass, Class } from "type-fest"
+import { z } from "zod"
+import { SchemableClass } from "."
+import { StaticMembers } from "./util"
+
+
+export function extendSchemableClass<
+    C extends SchemableClass<
+        ExtendSchemaT,
+        ExtendSchemaUnknownKeys,
+        ExtendSchemaCatchall,
+        ExtendSchemaValues,
+        ExtendDefaultValues
+    >,
+
+    ExtendSchemaT           extends z.ZodRawShape,
+    ExtendSchemaUnknownKeys extends z.UnknownKeysParam,
+    ExtendSchemaCatchall    extends z.ZodTypeAny,
+    ExtendSchemaValues      extends {},
+    ExtendDefaultValues     extends Partial<ExtendSchemaValues>,
+
+    SchemaT                 extends z.ZodRawShape,
+    SchemaUnknownKeys       extends z.UnknownKeysParam,
+    SchemaCatchall          extends z.ZodTypeAny,
+    SchemaValues            extends ExtendSchemaValues,
+    DefaultValues           extends Partial<SchemaValues>,
+>(
+    extend: C | SchemableClass<
+        ExtendSchemaT,
+        ExtendSchemaUnknownKeys,
+        ExtendSchemaCatchall,
+        ExtendSchemaValues,
+        ExtendDefaultValues
+    >,
+
+    schemaApplier: (schema: C["schema"]) => z.ZodObject<
+        SchemaT,
+        SchemaUnknownKeys,
+        SchemaCatchall,
+        SchemaValues,
+        SchemaValues
+    >,
+
+    defaultValuesApplier: (defaultValues: ExtendDefaultValues) => DefaultValues,
+) {
+    type ClassKind<T, Arguments extends unknown[]> = (
+        C extends Class<any>
+            ? Class<T, Arguments>
+            : AbstractClass<T, Arguments>
+    )
+
+    const schema        = schemaApplier(extend.schema)
+    const defaultValues = defaultValuesApplier(extend.defaultValues)
+
+    return class extends extend {
+        static readonly schema = schema
+               readonly schema = schema
+
+        static readonly defaultValues = defaultValues
+               readonly defaultValues = defaultValues
+    } as unknown as (
+        ClassKind<
+            Omit<C, "schema" | "defaultValues" | keyof ExtendSchemaValues> &
+            {
+                readonly schema:         typeof schema,
+                readonly defaultValues:  typeof defaultValues,
+            } &
+            SchemaValues,
+
+            ConstructorParameters<C>
+        > &
+
+        Omit<StaticMembers<C>, "schema" | "defaultValues"> &
+        {
+            readonly schema:         typeof schema,
+            readonly defaultValues:  typeof defaultValues,
+        }
+    )
+}