Basically library structure

src/utils/context.ts

@@ -1,6 +1,7 @@
-import { Fetcher } from '@/utils/fetcher';
+import { UseableFetcher } from '@/fetchers/types';
 
 export interface ScrapeContext {
-  proxiedFetcher: Fetcher;
-  fetcher: Fetcher;
+  proxiedFetcher: UseableFetcher;
+  fetcher: UseableFetcher;
+  progress(val: number): void;
 }

src/utils/fetcher.ts

@@ -1,11 +0,0 @@
-export type FetcherOptions = {
-  baseUrl?: string;
-  headers?: Record<string, string>;
-  query?: Record<string, string>;
-  method?: 'GET' | 'POST';
-  body?: Record<string, any> | string | FormData;
-};
-
-export type Fetcher<T = any> = {
-  (url: string, ops?: FetcherOptions): T;
-};

src/utils/predicates.ts

@@ -0,0 +1,7 @@
+export function isNotNull<T>(value: T | null | undefined): value is T {
+  return value !== null && value !== undefined;
+}
+
+export function hasDuplicates<T>(values: Array<T>): boolean {
+  return new Set(values).size !== values.length;
+}