CORS, EK, BROWSER, SECURITY, MECHANISM, hai — DIFFERENT, ORIGIN, (DOMAIN/PORT) SE, AANE, WALI, REQUESTS, ko, DEFAULT, mein, BLOCK, kiya, jaata hai (SAME-ORIGIN, POLICY). SERVER, ko, EXPLICITLY, ALLOW, karna, PADТA, hai, ki, KAUN, se, ORIGINS, se, REQUESTS, ACCEPT, kiye, jaayenge.

cors, NPM, PACKAGE, se, EASILY, CONFIGURE, kiya, ja, sakta hai — origin, OPTION, SE, SPECIFIC, DOMAINS, ALLOW, kiye, ja, sakte, hain, credentials: true, se, COOKIES, ke, saath, CROSS-ORIGIN, REQUESTS, ALLOW, hote, hain.

const cors = require("cors");

app.use(cors({
  origin: ["https://myapp.com", "https://admin.myapp.com"],
  credentials: true,   // cookies, ke, saath, requests, allow
}));

// Specific route, PAR, bhi, apply, kiya, ja, sakta hai:
app.get("/api/data", cors({ origin: "https://partner.com" }), handler);