fix: Add types to server properties (#4100)

* add types to validatorCompiler & serializerCompiler

* tests for the type addition

test/types/instance.test-d.ts

@@ -11,7 +11,7 @@ import { HookHandlerDoneFunction } from '../../types/hooks'
 import { FastifyReply } from '../../types/reply'
 import { FastifyRequest } from '../../types/request'
 import { DefaultRoute } from '../../types/route'
-import { FastifySchemaControllerOptions } from '../../types/schema'
+import { FastifySchemaControllerOptions, FastifySchemaCompiler, FastifySerializerCompiler } from '../../types/schema'
 
 const server = fastify()
 
@@ -325,3 +325,6 @@ expectType<void>(server.addConstraintStrategy(versionConstraintStrategy))
 expectType<boolean>(server.hasConstraintStrategy(versionConstraintStrategy.name))
 
 expectAssignable<DefaultRoute<RawRequestDefaultExpression, RawReplyDefaultExpression>>(server.getDefaultRoute())
+
+expectType<FastifySchemaCompiler<any> | undefined>(server.validatorCompiler)
+expectType<FastifySerializerCompiler<any> | undefined>(server.serializerCompiler)

types/instance.d.ts

@@ -550,11 +550,21 @@ export interface FastifyInstance<
     handler: (this: FastifyInstance<RawServer, RawRequest, RawReply, Logger, TypeProvider>, error: TError, request: FastifyRequest<RouteGeneric, RawServer, RawRequest, SchemaCompiler, TypeProvider>, reply: FastifyReply<RawServer, RawRequest, RawReply, RouteGeneric, ContextConfigDefault, SchemaCompiler, TypeProvider>) => any | Promise<any>
   ): FastifyInstance<RawServer, RawRequest, RawReply, Logger, TypeProvider>;
 
+  /**
+   * Fastify schema validator for all routes.
+   */
+  validatorCompiler: FastifySchemaCompiler<any> | undefined;
+
   /**
    * Set the schema validator for all routes.
    */
   setValidatorCompiler<T = FastifySchema>(schemaCompiler: FastifySchemaCompiler<T>): FastifyInstance<RawServer, RawRequest, RawReply, Logger, TypeProvider>;
 
+  /**
+   * Fastify schema serializer for all routes.
+   */
+  serializerCompiler: FastifySerializerCompiler<any> | undefined;
+
   /**
    * Set the schema serializer for all routes.
    */