چیت‌شیت TypeScript

1function formatName(first: string, last: string): string {2  return `${first} ${last}`;3}

1function greet(name: string, prefix = "Hello"): string {2  return `${prefix}, ${name}`;3}45greet("Sam");6greet("Sam", "Welcome");

1function isString(value: unknown): value is string {2  return typeof value === "string";3}45function lengthOf(value: unknown) {6  return isString(value) ? value.length : 0;7}

1function first<T>(items: readonly T[]): T | undefined {2  return items[0];3}45const firstId = first([10, 20]);

1interface Identified {2  id: string;3}45interface Product extends Identified {6  name: string;7  price: number;8}

1const settings = {2  mode: "compact",3  retries: 3,4} as const;56type Settings = typeof settings;

1type User = { id: string; name: string; email: string };23type UserUpdate = Partial<Pick<User, "name" | "email">>;4type PublicUser = Omit<User, "email">;

1type Theme = "light" | "dark";2const labels: Record<Theme, string> = {3  light: "روشن",4  dark: "تیره",5};67type LabelKey = keyof typeof labels;

1export type { User } from "./user";2export { createUser } from "./user";34import { createUser } from "./user";

1function printId(value: string | number) {2  if (typeof value === "number") {3    return value.toFixed(0);4  }5  return value.toUpperCase();6}

1{2  "compilerOptions": {3    "strict": true,4    "noEmit": true5  }6}