Utility turlari

type Mahsulot = { nomi: string; narx: number; tavsif: string };

function yangila(m: Mahsulot, ozgarish: Partial<Mahsulot>): Mahsulot {
  return { ...m, ...ozgarish };
}

const m: Mahsulot = { nomi: "Olma", narx: 12000, tavsif: "shirin" };
console.log(yangila(m, { narx: 15000 }));

tsx src/partial.ts

type Sozlama = { port?: number; host?: string };
type Toliq = Required<Sozlama>;

const s: Toliq = { port: 8080, host: "localhost" };
console.log(s.port, s.host);

tsx src/required.ts

type Sozlama = { port?: number; host?: string };
type Toliq = Required<Sozlama>;

const s: Toliq = { port: 8080 };

tsc --noEmit 2>&1 | fold -sw 74

type Dokon = { nomi: string; manzil: { shahar: string } };

const d: Readonly<Dokon> = {
  nomi: "Dokon",
  manzil: { shahar: "Toshkent" },
};

d.nomi = "Yangi";
d.manzil.shahar = "Samarqand";

tsc --noEmit 2>&1 | fold -sw 74

type Dokon = { nomi: string; manzil: { shahar: string } };

const d: Readonly<Dokon> = {
  nomi: "Dokon",
  manzil: { shahar: "Toshkent" },
};

d.manzil.shahar = "Samarqand";
console.log(d.manzil.shahar);

tsc --noEmit && echo "tsc: xato yo_q"
tsx src/readonly2.ts

type Mahsulot = {
  id: number;
  nomi: string;
  narx: number;
  tavsif: string;
};

type Qisqa = Pick<Mahsulot, "nomi" | "narx">;
type Yangi = Omit<Mahsulot, "id">;

const a: Qisqa = { nomi: "Olma", narx: 12000 };
const b: Yangi = { nomi: "Anor", narx: 25000, tavsif: "nordon" };

console.log(a.nomi, b.tavsif);

tsx src/pick.ts

type Mahsulot = { id: number; nomi: string };

type A = Omit<Mahsulot, "rang">;
type B = Pick<Mahsulot, "rang">;

const a: A = { id: 1, nomi: "Olma" };
console.log(a.nomi);

tsc --noEmit 2>&1 | fold -sw 74

type Pick<T, K extends keyof T> = ...
type Omit<T, K extends keyof any> = ...

type Daraja = "past" | "orta" | "yuqori";

const narxlar: Record<Daraja, number> = {
  past: 5000,
  orta: 12000,
  yuqori: 30000,
};

console.log(narxlar.orta);

tsx src/record.ts

type Daraja = "past" | "orta" | "yuqori";

const narxlar: Record<Daraja, number> = { past: 5000 };

tsc --noEmit 2>&1 | fold -sw 74

type Hamma = "olma" | "anor" | "uzum" | null;

type Qolgan = Exclude<Hamma, "uzum" | null>;
type Olingan = Extract<Hamma, "olma" | "shaftoli">;
type Bosh = NonNullable<Hamma>;

const a: Qolgan = "olma";
const b: Olingan = "olma";
const c: Bosh = "uzum";

console.log(a, b, c);

tsx src/union.ts

function yarat(nomi: string, narx: number) {
  return { nomi, narx, faol: true };
}

type Mahsulot = ReturnType<typeof yarat>;
type Args = Parameters<typeof yarat>;

const m: Mahsulot = { nomi: "Olma", narx: 12000, faol: false };
const a: Args = ["Anor", 25000];

console.log(m.nomi, a[1], yarat(...a).faol);

tsx src/rettype.ts

async function narxi(): Promise<number> {
  return 12000;
}

type N = Awaited<ReturnType<typeof narxi>>;

const n: N = 12000;
console.log(n.toFixed(2));

tsx src/awaited.ts

const DARAJALAR = ["past", "orta", "yuqori"] as const;

type Daraja = (typeof DARAJALAR)[number];

const d: Daraja = "orta";
console.log(DARAJALAR.length, d);

for (const x of DARAJALAR) console.log(x);

tsx src/asconst.ts

const DARAJALAR = ["past", "orta", "yuqori"] as const;
type Daraja = (typeof DARAJALAR)[number];

const d: Daraja = "juda";

tsc --noEmit 2>&1 | fold -sw 74

type MeningPartial<T> = { [K in keyof T]?: T[K] };
type Nullable<T> = { [K in keyof T]: T[K] | null };

type Mahsulot = { nomi: string; narx: number };

const a: MeningPartial<Mahsulot> = { nomi: "Olma" };
const b: Nullable<Mahsulot> = { nomi: null, narx: 12000 };

console.log(a.nomi, b.nomi, b.narx);

tsx src/oz.ts

type Getterlar<T> = {
  [K in keyof T as `ol${Capitalize<string & K>}`]: () => T[K];
};

type Mahsulot = { nomi: string; narx: number };

const m: Getterlar<Mahsulot> = {
  olNomi: () => "Olma",
  olNarx: () => 12000,
};

console.log(m.olNomi(), m.olNarx());

tsx src/getter.ts

type ChuqurReadonly<T> = {
  readonly [K in keyof T]: T[K] extends object
    ? ChuqurReadonly<T[K]>
    : T[K];
};

type Dokon = { nomi: string; manzil: { shahar: string } };

declare const d: ChuqurReadonly<Dokon>;
d.manzil.shahar = "Samarqand";

tsc --noEmit 2>&1 | fold -sw 74