Apa iku jenis utilitas kaya Partial, Pick lan Omit?

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**Jenis utilitas** yaiku jenis generik bawaan sing ngowahi jenis-jenis sing wis ana, supaya sampeyan bisa nggawe jenis-jenis anyar tanpa perlu nggawe ulang. Mula jenis-jenis tetep DRY lan sinkron karo asal-usule. ```ts interface User { id: number; name: string; email: string; age: number; } Partial; // all properties optional → for update payloads Required; // all properties required Readonly; // all properties readonly Pick; // { id, name } — keep only these Omit; // everything except id → for create payloads ``` ## Kenapa ngubah luwih apik tinimbang nggawe ulang ```ts // Update endpoint: accept any subset of fields function update(id: number, changes: Partial) { ... } update(1, { name: "New" }); // ✅ only the fields you change // Create endpoint: everything except the server-generated id type CreateUser = Omit; ``` Yen sampeyan nambah sawah ing `User`, kabeh iki nganyari kanthi otomatis — ora ana definisi kapindho sing kudu dieling. ## Luwih akeh sing mangpaat ```ts Record; // { [key: string]: number } — dictionaries ReturnType; // the return type of a function Parameters; // tuple of a function's parameter types NonNullable; // string (strips null/undefined) Extract; Exclude; // filter members of a union ``` ## Kenapa kuwi penting Jenis utilitas ngidini sampeyan ngungkapake hubungan ing antarane jenis-jenis ("formulir gawe yaiku user dikurangi id") kanthi deklaratif. Mula ngurangi duplikasi, njaga jenis-jenis sing diturunake tetep konsisten karo sumberan, lan ana ing mana-mana ing basis kode nyata — utamane `Partial` kanggo nganyari, `Omit`/`Pick` kanggo DTO, lan `Record` kanggo peta.