Feat: Create custom header changer (#694)

* Add custom header adder

* Make custom headers work in apip

* remove unnecesarry console.logs

* Remove add-cookie button remains

* getFile and remove unnecesarry ifs

* Add warning and copy to code function

libs/fetch.ts

@@ -1,48 +1,69 @@
 export async function fetchApi(
     url: string,
     init?: {
-        headers?: Record<string,string> | Headers;
-        [x: string]: string | Record<string,string> | undefined | FormData | Headers;
-    },
+        headers?: Record<string, string> | Headers;
+        [x: string]:
+            | string
+            | Record<string, string>
+            | undefined
+            | FormData
+            | Headers;
+    }
 ) {
-    let defaultHeaders: {
-        'User-Agent'?: string,
-        'Cookie'?: string,
-    } = {};
+    let defaultHeaders: Record<string, string> = {};
     try {
-        const getHeaders = (await import('../index.js')).getHeaders;
+        const { getHeaders } = await import("../index.js");
         defaultHeaders = getHeaders();
-    }catch{
+    } catch {
         // nothing to do
     }
-
-    if(init?.headers) {
-        if(init.headers instanceof Headers){ 
-            if(!init.headers.get('User-Agent') && defaultHeaders['User-Agent']){
-                init.headers.set('User-Agent', defaultHeaders['User-Agent']);
+    if (init?.headers) {
+        if (init.headers instanceof Headers) {
+            for (const [name, value] of Object.entries(defaultHeaders)) {
+                if (!init.headers.get(name)) init.headers.set(name, value);
             }
-            if(defaultHeaders.Cookie) {
-                init.headers.set('Cookie', defaultHeaders.Cookie);
-            }
-        }else{
+        } else {
             init.headers = {
                 ...defaultHeaders,
                 ...init.headers,
             };
         }
-    }else{
+    } else {
         init = {
             ...init,
-            headers: defaultHeaders
-        }
+            headers: defaultHeaders,
+        };
     }
-
     console.log(url, init);
     return await fetch(url, init);
 }
 
 export const fetchFile = async function (url: string, init?: RequestInit) {
     if (!init) init = {};
+    let defaultHeaders: Record<string, string> = {};
+    try {
+        const { getHeaders } = await import("../index.js");
+        defaultHeaders = getHeaders();
+    } catch {
+        // nothing to do
+    }
+    if (init?.headers) {
+        if (init.headers instanceof Headers) {
+            for (const [name, value] of Object.entries(defaultHeaders)) {
+                if (!init.headers.get(name)) init.headers.set(name, value);
+            }
+        } else {
+            init.headers = {
+                ...defaultHeaders,
+                ...init.headers,
+            };
+        }
+    } else {
+        init = {
+            ...init,
+            headers: defaultHeaders,
+        };
+    }
     try {
         const res = await fetch(url, init);
         if (!res.ok) return undefined;