Apa sing ditindakne operator satisfies?

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Accepted Answer

`satisfies` (TS 4.9+) mriksa yen nilai **sesuai karo** tipe **tanpa nglebar** tipe sing diuruk saka nilai kasebut. Iki ngesahake lawan konstraen nalika tetep tipe sing presisi lan literal kanggo panggunan sabanjure — sing paling apik saka anotasi lan inferensi. ## Masalah sing dirungokake ```ts type Config = Record; // annotation widens — you lose the specific keys/values const a: Config = { host: "localhost", port: 3000 }; a.port.toFixed(2); // ❌ port is string | number, .toFixed may not exist // satisfies — validates AND keeps the narrow inferred type const b = { host: "localhost", port: 3000 } satisfies Config; b.port.toFixed(2); // ✅ port is known to be number b.host.toUpperCase(); // ✅ host is known to be string // b.hsot; // ✅ compile error — only real keys exist ``` Karo anotasi, `b` bakal dituping minangka `Config` sing lebar. Karo `satisfies`, `b` tetep wujude sing pas `{ host: string; port: number }` *lan* dieksamen dadi `Config` sing sah. ## Liyane klasik: lookup sing akeh jeneng sing sampeyan tetep pengin eksak ```ts const routes = { home: "/", user: "/users/:id", } satisfies Record; type RouteName = keyof typeof routes; // "home" | "user" — exact keys preserved ``` ## satisfies vs `as` vs anotasi - **`: T`** — mriksa, nanging nglebar dadi `T` (ilang rincian). - **`as T`** — maksa tipe, *ora* nyata mriksa (ora aman). - **`satisfies T`** — mriksa lawan `T`, tetep tipe sing diuruk sing sempit (aman + presisi). ## Kenapa iki penting `satisfies` ngidini sampeyan ngesahake yen obyek cocok karo antarmuka/konstraen nalika tetep entuk tipe literal sing eksak kanggo autocomplete, narrowing, lan `keyof`. Iki cocok kanggo obyek konfigurasi, peta rute, palet tema, lan pencarian konstanta ing ngendi sampeyan pengin kapunten *lan* inferensi presisi.

Masalah sing dirungokake

Liyane klasik: lookup sing akeh jeneng sing sampeyan tetep pengin eksak

satisfies vs as vs anotasi

Kenapa iki penting

satisfies vs `as` vs anotasi