Refactor: Improve readability of create link function

functions/api/links/create.js

@@ -1 +1,42 @@
-const genSlug=l=>[...Array(l)].map(()=>"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"[Math.random()*62|0]).join(""),R=new Set(["api","dash","admin","login","logout","signin","signup","register","account","settings","profile","password","user","users","link","links","url","urls","robots","sitemap","favicon","well-known","assets","static","img","js","css","public"]);export async function onRequestPost({request:r,env:e}){try{const{'g-recaptcha-response':t,...b}=await r.json(),v=await fetch("https://www.google.com/recaptcha/api/siteverify",{method:"POST",headers:{"Content-Type":"application/x-www-form-urlencoded"},body:`secret=${e.RECAPCHA_KEY}&response=${t}`}).then(r=>r.json());if(!v.success)return new Response("CAPTCHA verification failed.",{status:403});const{destination_url:d,slug:s,username:u,pass_hash:h}=b;if(!d||!u||!h)return new Response("Missing fields",{status:400});const a=await e.D1_EV.prepare("SELECT pass_hash, custom_slugs FROM users WHERE username = ?").bind(u).first();if(a?.pass_hash!==h)return new Response("Invalid credentials",{status:401});let i=s;if(i){if(R.has(i.toLowerCase())||!/^[a-zA-Z0-9-]{3,32}$/.test(i)||await e.KV_EV.get(i))return new Response("Invalid or taken slug",{status:400})}else{do{i=genSlug(6)}while(await e.KV_EV.get(i))}let o=d.startsWith("http")?d:`https://${d}`;try{new URL(o)}catch{return new Response("Invalid destination URL",{status:400})}const n=o.replace(/^https?:\/\//,"");let p;try{p=JSON.parse(a.custom_slugs)}catch(r){}const c=Array.isArray(p)?p:[];c.push(i);await Promise.all([e.KV_EV.put(i,n),e.D1_EV.prepare("UPDATE users SET custom_slugs = ? WHERE username = ?").bind(JSON.stringify(c),u).run()]);return Response.json({slug:i},{status:201})}catch(r){return new Response(r.message,{status:500})}}
+const genSlug = l => [...Array(l)].map(() => "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" [Math.random() * 62 | 0]).join("");
+const RESERVED = new Set(["api", "dash", "admin", "login", "logout", "signin", "signup", "register", "account", "settings", "profile", "password", "user", "users", "link", "links", "url", "urls", "robots", "sitemap", "favicon", "well-known", "assets", "static", "img", "js", "css", "public"]);
+
+export async function onRequestPost({ request, env }) {
+    try {
+        const { 'g-recaptcha-response': token, ...body } = await request.json();
+        const vR = await fetch("https://www.google.com/recaptcha/api/siteverify", { method: "POST", headers: { "Content-Type": "application/x-www-form-urlencoded" }, body: `secret=${env.RECAPCHA_KEY}&response=${token}` });
+        if (!(await vR.json()).success) return new Response("CAPTCHA verification failed.", { status: 403 });
+
+        const { destination_url, slug, username, pass_hash } = body;
+        if (!destination_url || !username || !pass_hash) return new Response("Missing fields", { status: 400 });
+
+        const user = await env.D1_EV.prepare("SELECT pass_hash, custom_slugs FROM users WHERE username = ?").bind(username).first();
+        if (user?.pass_hash !== pass_hash) return new Response("Invalid credentials", { status: 401 });
+
+        let finalSlug = slug;
+        if (finalSlug) {
+            if (RESERVED.has(finalSlug.toLowerCase()) || !/^[a-zA-Z0-9-]{3,32}$/.test(finalSlug) || await env.KV_EV.get(finalSlug))
+                return new Response("Invalid or taken slug", { status: 400 });
+        } else {
+            do { finalSlug = genSlug(6) } while (await env.KV_EV.get(finalSlug));
+        }
+
+        let url = destination_url.startsWith("http") ? destination_url : `https://${destination_url}`;
+        try { new URL(url) } catch { return new Response("Invalid destination URL", { status: 400 }) }
+        
+        const dest_no_proto = url.replace(/^https?:\/\//, "");
+        let slugs;
+        try { slugs = JSON.parse(user.custom_slugs) } catch {}
+        const newSlugs = Array.isArray(slugs) ? slugs : [];
+        newSlugs.push(finalSlug);
+
+        await Promise.all([
+            env.KV_EV.put(finalSlug, dest_no_proto),
+            env.D1_EV.prepare("UPDATE users SET custom_slugs = ? WHERE username = ?").bind(JSON.stringify(newSlugs), username).run()
+        ]);
+
+        return Response.json({ slug: finalSlug }, { status: 201 });
+    } catch (e) {
+        return new Response(e.message, { status: 500 });
+    }
+}