make and use a single validator type

extended_request_init.ts

@@ -9,12 +9,16 @@ interface RequestInitDiff {
   body?: Record<string, unknown> | BodyInit | null;
   /** a function that will be called before returning response.
    *  can be used for validating response and throwing errors */
-  validator?:
-    ((response: Response, init: ExtendedRequestInit) => void | Promise<void>);
+  validator?: Validator;
   /** time in milliseconds which after the request should be cancelled and rejected */
   timeout?: number;
 }
 
+export type Validator = (
+  response: Response,
+  init: ExtendedRequestInit,
+) => void | Promise<void>;
+
 export type ExtendedRequestInit =
   & RequestInitDiff
   & Omit<RequestInit, keyof RequestInitDiff>;

fetch_wrapper.ts

@@ -1,6 +1,6 @@
 import * as utils from "./utils.ts";
 import { getHeader, setHeader } from "./header_utils.ts";
-import { ExtendedRequestInit } from "./extended_request_init.ts";
+import { ExtendedRequestInit, Validator } from "./extended_request_init.ts";
 
 /**
  * Transforms data and adds corresponding headers if possible.
@@ -80,8 +80,7 @@ export type WrapFetchOptions = {
   /** user agent header string */
   userAgent?: string;
   /** validator to run after each response with this fetch */
-  validator?:
-    ((response: Response, init: ExtendedRequestInit) => void | Promise<void>);
+  validator?: Validator;
   /** if set, all requests will timeout after this amount of milliseconds passed */
   timeout?: number;
 };