function between<T>(a1: T, a2: T, a3: T): boolean {
  return a2 <= a1 && a1 <= a3;
}

function between<T>(value: T, left: T, right: T): boolean {
  return left <= value && value <= right;
}

type DtaRcrd102 = {
  genymdhms: Date;
  modymdhms: Date;
  pszqint: number;
}

type Customer = {
  generationTimestamp: Date;
  modificationTimestamp: Date;
  recordId: number;
}

function getUserInfo(): User;
function getUserDetails(): User;
function getUserData(): User;

function getUser(): User;

// 86400000이 도대체 뭐지?
setTimeout(restart, 86400000);

// 대문자로 이루어진 상수로 선언하세요.
const MILLISECONDS_IN_A_DAY = 24 * 60 * 60 * 1000;

setTimeout(restart, MILLISECONDS_IN_A_DAY);

declare const users: Map<string, User>;

for (const keyValue of users) {
  // users 맵을 순회
}

declare const users: Map<string, User>;

for (const [id, user] of users) {
  // users 맵을 순회
}

const u = getUser();
const s = getSubscription();
const t = charge(u, s);

const user = getUser();
const subscription = getSubscription();
const transaction = charge(user, subscription);

type Car = {
  carMake: string;
  carModel: string;
  carColor: string;
}

function print(car: Car): void {
  console.log(`${car.carMake} ${car.carModel} (${car.carColor})`);
}

type Car = {
  make: string;
  model: string;
  color: string;
}

function print(car: Car): void {
  console.log(`${car.make} ${car.model} (${car.color})`);
}

function loadPages(count?: number) {
  const loadCount = count !== undefined ? count : 10;
  // ...
}

function loadPages(count: number = 10) {
  // ...
}

const GENRE = {
  ROMANTIC: 'romantic',
  DRAMA: 'drama',
  COMEDY: 'comedy',
  DOCUMENTARY: 'documentary',
}

projector.configureFilm(GENRE.COMEDY);

class Projector {
  // Projector의 선언
  configureFilm(genre) {
    switch (genre) {
      case GENRE.ROMANTIC:
        // 실행되어야 하는 로직
    }
  }
}

enum GENRE {
  ROMANTIC,
  DRAMA,
  COMEDY,
  DOCUMENTARY,
}

projector.configureFilm(GENRE.COMEDY);

class Projector {
  // Projector의 선언
  configureFilm(genre) {
    switch (genre) {
      case GENRE.ROMANTIC:
        // 실행되어야 하는 로직
    }
  }
}

function createMenu(title: string, body: string, buttonText: string, cancellable: boolean) {
  // ...
}

createMenu('Foo', 'Bar', 'Baz', true);

function createMenu(options: { title: string, body: string, buttonText: string, cancellable: boolean }) {
  // ...
}

createMenu({
  title: 'Foo',
  body: 'Bar',
  buttonText: 'Baz',
  cancellable: true
});

type MenuOptions = { title: string, body: string, buttonText: string, cancellable: boolean };

function createMenu(options: MenuOptions) {
  // ...
}

createMenu({
  title: 'Foo',
  body: 'Bar',
  buttonText: 'Baz',
  cancellable: true
});

function emailClients(clients: Client[]) {
  clients.forEach((client) => {
    const clientRecord = database.lookup(client);
    if (clientRecord.isActive()) {
      email(client);
    }
  });
}

function emailClients(clients: Client[]) {
  clients.filter(isActiveClient).forEach(email);
}

function isActiveClient(client: Client) {
  const clientRecord = database.lookup(client);
  return clientRecord.isActive();
}

function addToDate(date: Date, month: number): Date {
  // ...
}

const date = new Date();

// 무엇이 추가되는지 함수 이름만으로 유추하기 어렵습니다
addToDate(date, 1);

function addMonthToDate(date: Date, month: number): Date {
  // ...
}

const date = new Date();
addMonthToDate(date, 1);

function parseCode(code: string) {
  const REGEXES = [ /* ... */ ];
  const statements = code.split(' ');
  const tokens = [];

  REGEXES.forEach((regex) => {
    statements.forEach((statement) => {
      // ...
    });
  });

  const ast = [];
  tokens.forEach((token) => {
    // lex...
  });

  ast.forEach((node) => {
    // parse...
  });
}

const REGEXES = [ /* ... */ ];

function parseCode(code: string) {
  const tokens = tokenize(code);
  const syntaxTree = parse(tokens);

  syntaxTree.forEach((node) => {
    // parse...
  });
}

function tokenize(code: string): Token[] {
  const statements = code.split(' ');
  const tokens: Token[] = [];

  REGEXES.forEach((regex) => {
    statements.forEach((statement) => {
      tokens.push( /* ... */ );
    });
  });

  return tokens;
}

function parse(tokens: Token[]): SyntaxTree {
  const syntaxTree: SyntaxTree[] = [];
  tokens.forEach((token) => {
    syntaxTree.push( /* ... */ );
  });

  return syntaxTree;
}

function showDeveloperList(developers: Developer[]) {
  developers.forEach((developer) => {
    const expectedSalary = developer.calculateExpectedSalary();
    const experience = developer.getExperience();
    const githubLink = developer.getGithubLink();

    const data = {
      expectedSalary,
      experience,
      githubLink
    };

    render(data);
  });
}

function showManagerList(managers: Manager[]) {
  managers.forEach((manager) => {
    const expectedSalary = manager.calculateExpectedSalary();
    const experience = manager.getExperience();
    const portfolio = manager.getMBAProjects();

    const data = {
      expectedSalary,
      experience,
      portfolio
    };

    render(data);
  });
}

class Developer {
  // ...
  getExtraDetails() {
    return {
      githubLink: this.githubLink,
    }
  }
}

class Manager {
  // ...
  getExtraDetails() {
    return {
      portfolio: this.portfolio,
    }
  }
}

function showEmployeeList(employee: Developer | Manager) {
  employee.forEach((employee) => {
    const expectedSalary = employee.calculateExpectedSalary();
    const experience = employee.getExperience();
    const extra = employee.getExtraDetails();

    const data = {
      expectedSalary,
      experience,
      extra,
    };

    render(data);
  });
}

type MenuConfig = { title?: string, body?: string, buttonText?: string, cancellable?: boolean };

function createMenu(config: MenuConfig) {
  config.title = config.title || 'Foo';
  config.body = config.body || 'Bar';
  config.buttonText = config.buttonText || 'Baz';
  config.cancellable = config.cancellable !== undefined ? config.cancellable : true;

  // ...
}

createMenu({ body: 'Bar' });

type MenuConfig = { title?: string, body?: string, buttonText?: string, cancellable?: boolean };

function createMenu(config: MenuConfig) {
  const menuConfig = Object.assign({
    title: 'Foo',
    body: 'Bar',
    buttonText: 'Baz',
    cancellable: true
  }, config);

  // ...
}

createMenu({ body: 'Bar' });

type MenuConfig = { title?: string, body?: string, buttonText?: string, cancellable?: boolean };

function createMenu({ title = 'Foo', body = 'Bar', buttonText = 'Baz', cancellable = true }: MenuConfig) {
  // ...
}

createMenu({ body: 'Bar' });

function createFile(name: string, temp: boolean) {
  if (temp) {
    fs.create(`./temp/${name}`);
  } else {
    fs.create(name);
  }
}

function createTempFile(name: string) {
  createFile(`./temp/${name}`);
}

function createFile(name: string) {
  fs.create(name);
}

// 아래의 함수에서 참조하는 전역 변수입니다.
let name = 'Robert C. Martin';

function toBase64() {
  name = btoa(name);
}

toBase64();
// 이 이름을 사용하는 다른 함수가 있다면, 그것은 Base64 값을 반환할 것입니다

console.log(name); // 'Robert C. Martin'이 출력되는 것을 예상했지만 'Um9iZXJ0IEMuIE1hcnRpbg=='가 출력됨

const name = 'Robert C. Martin';

function toBase64(text: string): string {
  return btoa(text);
}

const encodedName = toBase64(name);
console.log(name);

function addItemToCart(cart: CartItem[], item: Item): void {
  cart.push({ item, date: Date.now() });
};

function addItemToCart(cart: CartItem[], item: Item): CartItem[] {
  return [...cart, { item, date: Date.now() }];
};

declare global {
  interface Array<T> {
    diff(other: T[]): Array<T>;
  }
}

if (!Array.prototype.diff) {
  Array.prototype.diff = function <T>(other: T[]): T[] {
    const hash = new Set(other);
    return this.filter(elem => !hash.has(elem));
  };
}

class MyArray<T> extends Array<T> {
  diff(other: T[]): T[] {
    const hash = new Set(other);
    return this.filter(elem => !hash.has(elem));
  };
}

const contributions = [
  {
    name: 'Uncle Bobby',
    linesOfCode: 500
  }, {
    name: 'Suzie Q',
    linesOfCode: 1500
  }, {
    name: 'Jimmy Gosling',
    linesOfCode: 150
  }, {
    name: 'Gracie Hopper',
    linesOfCode: 1000
  }
];

let totalOutput = 0;

for (let i = 0; i < contributions.length; i++) {
  totalOutput += contributions[i].linesOfCode;
}

const contributions = [
  {
    name: 'Uncle Bobby',
    linesOfCode: 500
  }, {
    name: 'Suzie Q',
    linesOfCode: 1500
  }, {
    name: 'Jimmy Gosling',
    linesOfCode: 150
  }, {
    name: 'Gracie Hopper',
    linesOfCode: 1000
  }
];

const totalOutput = contributions
  .reduce((totalLines, output) => totalLines + output.linesOfCode, 0);

if (subscription.isTrial || account.balance > 0) {
  // ...
}

function canActivateService(subscription: Subscription, account: Account) {
  return subscription.isTrial || account.balance > 0;
}

if (canActivateService(subscription, account)) {
  // ...
}

function isEmailNotUsed(email: string): boolean {
  // ...
}

if (isEmailNotUsed(email)) {
  // ...
}

function isEmailUsed(email): boolean {
  // ...
}

if (!isEmailUsed(node)) {
  // ...
}

class Airplane {
  private type: string;
  // ...

  getCruisingAltitude() {
    switch (this.type) {
      case '777':
        return this.getMaxAltitude() - this.getPassengerCount();
      case 'Air Force One':
        return this.getMaxAltitude();
      case 'Cessna':
        return this.getMaxAltitude() - this.getFuelExpenditure();
      default:
        throw new Error('Unknown airplane type.');
    }
  }

  private getMaxAltitude(): number {
    // ...
  }
}

abstract class Airplane {
  protected getMaxAltitude(): number {
    // shared logic with subclasses ...
  }

  // ...
}

class Boeing777 extends Airplane {
  // ...
  getCruisingAltitude() {
    return this.getMaxAltitude() - this.getPassengerCount();
  }
}

class AirForceOne extends Airplane {
  // ...
  getCruisingAltitude() {
    return this.getMaxAltitude();
  }
}

class Cessna extends Airplane {
  // ...
  getCruisingAltitude() {
    return this.getMaxAltitude() - this.getFuelExpenditure();
  }
}

function travelToTexas(vehicle: Bicycle | Car) {
  if (vehicle instanceof Bicycle) {
    vehicle.pedal(currentLocation, new Location('texas'));
  } else if (vehicle instanceof Car) {
    vehicle.drive(currentLocation, new Location('texas'));
  }
}

type Vehicle = Bicycle | Car;

function travelToTexas(vehicle: Vehicle) {
  vehicle.move(currentLocation, new Location('texas'));
}

// 예전 브라우저에서는 캐시되지 않은 `list.length`를 사용한 각 순회는 비용이 많이 들 것입니다.
// `list.length`의 재계산 때문입니다. 현대 브라우저에서는 이 부분이 최적화됩니다.
for (let i = 0, len = list.length; i < len; i++) {
  // ...
}

for (let i = 0; i < list.length; i++) {
  // ...
}

function oldRequestModule(url: string) {
  // ...
}

function requestModule(url: string) {
  // ...
}

const req = requestModule;
inventoryTracker('apples', req, 'www.inventory-awesome.io');

function requestModule(url: string) {
  // ...
}

const req = requestModule;
inventoryTracker('apples', req, 'www.inventory-awesome.io');

function fibonacci(n: number): number[] {
  if (n === 1) return [0];
  if (n === 2) return [0, 1];

  const items: number[] = [0, 1];
  while (items.length < n) {
    items.push(items[items.length - 2] + items[items.length - 1]);
  }

  return items;
}

function print(n: number) {
  fibonacci(n).forEach(fib => console.log(fib));
}

// 피보나치 숫자의 첫 번째 10개 숫자를 출력합니다.
print(10);

// 피보나치 숫자의 무한 스트림을 생성합니다.
// `generator`는 모든 숫자의 배열을 유지하고 있지 않습니다.
function* fibonacci(): IterableIterator<number> {
  let [a, b] = [0, 1];

  while (true) {
    yield a;
    [a, b] = [b, a + b];
  }
}

function print(n: number) {
  let i = 0;
  for (const fib of fibonacci()) {
    if (i++ === n) break;  
    console.log(fib);
  }  
}

// 피보나치 숫자의 첫 번째 10개 숫자를 출력합니다.
print(10);

import itiriri from 'itiriri';

function* fibonacci(): IterableIterator<number> {
  let [a, b] = [0, 1];
 
  while (true) {
    yield a;
    [a, b] = [b, a + b];
  }
}

itiriri(fibonacci())
  .take(10)
  .forEach(fib => console.log(fib));

type BankAccount = {
  balance: number;
  // ...
}

const value = 100;
const account: BankAccount = {
  balance: 0,
  // ...
};

if (value < 0) {
  throw new Error('Cannot set negative balance.');
}

account.balance = value;

class BankAccount {
  private accountBalance: number = 0;

  get balance(): number {
    return this.accountBalance;
  }

  set balance(value: number) {
    if (value < 0) {
      throw new Error('Cannot set negative balance.');
    }

    this.accountBalance = value;
  }

  // ...
}

// 이제 `BankAccount`는 검증 로직을 캡슐화합니다.
// 명세가 바뀐다면, 추가적인 검증 규칙을 추가할 필요가 있습니다.
// 그 때, `setter` 구현부만 수정하면 됩니다.
// 관련있는 다른 코드는 변경할 필요가 없습니다.
const account = new BankAccount();
account.balance = 100;

class Circle {
  radius: number;
  
  constructor(radius: number) {
    this.radius = radius;
  }

  perimeter() {
    return 2 * Math.PI * this.radius;
  }

  surface() {
    return Math.PI * this.radius * this.radius;
  }
}

class Circle {
  constructor(private readonly radius: number) {
  }

  perimeter() {
    return 2 * Math.PI * this.radius;
  }

  surface() {
    return Math.PI * this.radius * this.radius;
  }
}

interface Config {
  host: string;
  port: string;
  db: string;
}

interface Config {
  readonly host: string;
  readonly port: string;
  readonly db: string;
}

const array: number[] = [ 1, 3, 5 ];
array = []; // 에러
array.push(100); // 배열은 변경될 것입니다.

const array: ReadonlyArray<number> = [ 1, 3, 5 ];
array = []; // 에러
array.push(100); // 에러

function hoge(args: readonly string[]) {
  args.push(1); // 에러
}

const config = {
  hello: 'world'
};
config.hello = 'world'; // 값이 바뀝니다

const array  = [ 1, 3, 5 ];
array[0] = 10; // 값이 바뀝니다

// 쓸 수 있는 객체가 반환됩니다
function readonlyData(value: number) {
  return { value };
}

const result = readonlyData(100);
result.value = 200; // 값이 바뀝니다

// 읽기 전용 객체
const config = {
  hello: 'world'
} as const;
config.hello = 'world'; // 에러

// 읽기 전용 배열
const array  = [ 1, 3, 5 ] as const;
array[0] = 10; // 에러

// 읽기 전용 객체를 반활할 수 있습니다
function readonlyData(value: number) {
  return { value } as const;
}

const result = readonlyData(100);
result.value = 200; // 에러

interface EmailConfig {
  // ...
}

interface DbConfig {
  // ...
}

interface Config {
  // ...
}

//...

type Shape = {
  // ...
}

type EmailConfig = {
  // ...
}

type DbConfig = {
  // ...
}

type Config  = EmailConfig | DbConfig;

// ...

interface Shape {
  // ...
}

class Circle implements Shape {
  // ...
}

class Square implements Shape {
  // ...
}

class Dashboard {
  getLanguage(): string { /* ... */ }
  setLanguage(language: string): void { /* ... */ }
  showProgress(): void { /* ... */ }
  hideProgress(): void { /* ... */ }
  isDirty(): boolean { /* ... */ }
  disable(): void { /* ... */ }
  enable(): void { /* ... */ }
  addSubscription(subscription: Subscription): void { /* ... */ }
  removeSubscription(subscription: Subscription): void { /* ... */ }
  addUser(user: User): void { /* ... */ }
  removeUser(user: User): void { /* ... */ }
  goToHomePage(): void { /* ... */ }
  updateProfile(details: UserDetails): void { /* ... */ }
  getVersion(): string { /* ... */ }
  // ...
}

class Dashboard {
  disable(): void { /* ... */ }
  enable(): void { /* ... */ }
  getVersion(): string { /* ... */ }
}

// 다른 클래스에 남은 메소드를 이동시킴으로써 책임을 분산시키세요
// ...

class UserManager {
  // Bad: 각 private 변수는 메소드의 하나 혹은 또 다른 그룹에 의해 사용됩니다.
  // 클래스가 단일 책임 이상의 책임을 가지고 있다는 명백한 증거입니다.
  // 사용자의 트랜잭션을 얻기 위해 서비스를 생성하기만 하면 되는 경우,
  // 여전히 `emailSender` 인스턴스를 전달해야 합니다.
  constructor(
    private readonly db: Database,
    private readonly emailSender: EmailSender) {
  }

  async getUser(id: number): Promise<User> {
    return await db.users.findOne({ id });
  }

  async getTransactions(userId: number): Promise<Transaction[]> {
    return await db.transactions.find({ userId });
  }

  async sendGreeting(): Promise<void> {
    await emailSender.send('Welcome!');
  }

  async sendNotification(text: string): Promise<void> {
    await emailSender.send(text);
  }

  async sendNewsletter(): Promise<void> {
    // ...
  }
}

class UserService {
  constructor(private readonly db: Database) {
  }

  async getUser(id: number): Promise<User> {
    return await this.db.users.findOne({ id });
  }

  async getTransactions(userId: number): Promise<Transaction[]> {
    return await this.db.transactions.find({ userId });
  }
}

class UserNotifier {
  constructor(private readonly emailSender: EmailSender) {
  }

  async sendGreeting(): Promise<void> {
    await this.emailSender.send('Welcome!');
  }

  async sendNotification(text: string): Promise<void> {
    await this.emailSender.send(text);
  }

  async sendNewsletter(): Promise<void> {
    // ...
  }
}

class Employee {
  constructor(
    private readonly name: string,
    private readonly email: string) {
  }

  // ...
}

// `Employee`가 세금 데이터를 가지기 때문에 나쁜 에입니다. `EmployeeTaxData`는 `Employee`의 타입이 아닙니다.
class EmployeeTaxData extends Employee {
  constructor(
    name: string,
    email: string,
    private readonly ssn: string,
    private readonly salary: number) {
    super(name, email);
  }

  // ...
}

class Employee {
  private taxData: EmployeeTaxData;

  constructor(
    private readonly name: string,
    private readonly email: string) {
  }

  setTaxData(ssn: string, salary: number): Employee {
    this.taxData = new EmployeeTaxData(ssn, salary);
    return this;
  }

  // ...
}

class EmployeeTaxData {
  constructor(
    public readonly ssn: string,
    public readonly salary: number) {
  }

  // ...
}

class QueryBuilder {
  private collection: string;
  private pageNumber: number = 1;
  private itemsPerPage: number = 100;
  private orderByFields: string[] = [];

  from(collection: string): void {
    this.collection = collection;
  }

  page(number: number, itemsPerPage: number = 100): void {
    this.pageNumber = number;
    this.itemsPerPage = itemsPerPage;
  }

  orderBy(...fields: string[]): void {
    this.orderByFields = fields;
  }

  build(): Query {
    // ...
  }
}

// ...

const queryBuilder = new QueryBuilder();
queryBuilder.from('users');
queryBuilder.page(1, 100);
queryBuilder.orderBy('firstName', 'lastName');

const query = queryBuilder.build();

class QueryBuilder {
  private collection: string;
  private pageNumber: number = 1;
  private itemsPerPage: number = 100;
  private orderByFields: string[] = [];

  from(collection: string): this {
    this.collection = collection;
    return this;
  }

  page(number: number, itemsPerPage: number = 100): this {
    this.pageNumber = number;
    this.itemsPerPage = itemsPerPage;
    return this;
  }

  orderBy(...fields: string[]): this {
    this.orderByFields = fields;
    return this;
  }

  build(): Query {
    // ...
  }
}

// ...

const query = new QueryBuilder()
  .from('users')
  .page(1, 100)
  .orderBy('firstName', 'lastName')
  .build();

class UserSettings {
  constructor(private readonly user: User) {
  }

  changeSettings(settings: UserSettings) {
    if (this.verifyCredentials()) {
      // ...
    }
  }

  verifyCredentials() {
    // ...
  }
}

class UserAuth {
  constructor(private readonly user: User) {
  }

  verifyCredentials() {
    // ...
  }
}


class UserSettings {
  private readonly auth: UserAuth;

  constructor(private readonly user: User) {
    this.auth = new UserAuth(user);
  }

  changeSettings(settings: UserSettings) {
    if (this.auth.verifyCredentials()) {
      // ...
    }
  }
}

class AjaxAdapter extends Adapter {
  constructor() {
    super();
  }

  // ...
}

class NodeAdapter extends Adapter {
  constructor() {
    super();
  }

  // ...
}

class HttpRequester {
  constructor(private readonly adapter: Adapter) {
  }

  async fetch<T>(url: string): Promise<T> {
    if (this.adapter instanceof AjaxAdapter) {
      const response = await makeAjaxCall<T>(url);
      // response 값을 변경하고 반환합니다.
    } else if (this.adapter instanceof NodeAdapter) {
      const response = await makeHttpCall<T>(url);
      // response 값을 변경하고 반환합니다.
    }
  }
}

function makeAjaxCall<T>(url: string): Promise<T> {
  // 서버에 요청하고 프로미스를 반환합니다.
}

function makeHttpCall<T>(url: string): Promise<T> {
  // 서버에 요청하고 프로미스를 반환합니다.
}

abstract class Adapter {
  abstract async request<T>(url: string): Promise<T>;

  // 하위 클래스와 공유하는 코드 ...
}

class AjaxAdapter extends Adapter {
  constructor() {
    super();
  }

  async request<T>(url: string): Promise<T>{
    // 서버에 요청하고 프로미스를 반환합니다.
  }

  // ...
}

class NodeAdapter extends Adapter {
  constructor() {
    super();
  }

  async request<T>(url: string): Promise<T>{
    // 서버에 요청하고 프로미스를 반환합니다.
  }

  // ...
}

class HttpRequester {
  constructor(private readonly adapter: Adapter) {
  }

  async fetch<T>(url: string): Promise<T> {
    const response = await this.adapter.request<T>(url);
    // response 값을 변경하고 반환합니다.
  }
}

class Rectangle {
  constructor(
    protected width: number = 0,
    protected height: number = 0) {

  }

  setColor(color: string): this {
    // ...
  }

  render(area: number) {
    // ...
  }

  setWidth(width: number): this {
    this.width = width;
    return this;
  }

  setHeight(height: number): this {
    this.height = height;
    return this;
  }

  getArea(): number {
    return this.width * this.height;
  }
}

class Square extends Rectangle {
  setWidth(width: number): this {
    this.width = width;
    this.height = width;
    return this;
  }

  setHeight(height: number): this {
    this.width = height;
    this.height = height;
    return this;
  }
}

function renderLargeRectangles(rectangles: Rectangle[]) {
  rectangles.forEach((rectangle) => {
    const area = rectangle
      .setWidth(4)
      .setHeight(5)
      .getArea(); // BAD: `Square` 클래스에서는 25를 반환합니다. 20이 반환되어야 합니다.
    rectangle.render(area);
  });
}

const rectangles = [new Rectangle(), new Rectangle(), new Square()];
renderLargeRectangles(rectangles);

abstract class Shape {
  setColor(color: string): this {
    // ...
  }

  render(area: number) {
    // ...
  }

  abstract getArea(): number;
}

class Rectangle extends Shape {
  constructor(
    private readonly width = 0,
    private readonly height = 0) {
    super();
  }

  getArea(): number {
    return this.width * this.height;
  }
}

class Square extends Shape {
  constructor(private readonly length: number) {
    super();
  }

  getArea(): number {
    return this.length * this.length;
  }
}

function renderLargeShapes(shapes: Shape[]) {
  shapes.forEach((shape) => {
    const area = shape.getArea();
    shape.render(area);
  });
}

const shapes = [new Rectangle(4, 5), new Rectangle(4, 5), new Square(5)];
renderLargeShapes(shapes);

interface SmartPrinter {
  print();
  fax();
  scan();
}

class AllInOnePrinter implements SmartPrinter {
  print() {
    // ...
  }  
  
  fax() {
    // ...
  }

  scan() {
    // ...
  }
}

class EconomicPrinter implements SmartPrinter {
  print() {
    // ...
  }  
  
  fax() {
    throw new Error('Fax not supported.');
  }

  scan() {
    throw new Error('Scan not supported.');
  }
}

interface Printer {
  print();
}

interface Fax {
  fax();
}

interface Scanner {
  scan();
}

class AllInOnePrinter implements Printer, Fax, Scanner {
  print() {
    // ...
  }  
  
  fax() {
    // ...
  }

  scan() {
    // ...
  }
}

class EconomicPrinter implements Printer {
  print() {
    // ...
  }
}

import { readFile as readFileCb } from 'fs';
import { promisify } from 'util';

const readFile = promisify(readFileCb);

type ReportData = {
  // ..
}

class XmlFormatter {
  parse<T>(content: string): T {
    // XML 문자열을 T 객체로 변환
  }
}

class ReportReader {

  // BAD: 특정 요청의 구현에 의존하는 것을 만들었습니다.
  // `parse` 메소드에 의존하는 `ReportReader`를 만들어야 합니다.
  private readonly formatter = new XmlFormatter();

  async read(path: string): Promise<ReportData> {
    const text = await readFile(path, 'UTF8');
    return this.formatter.parse<ReportData>(text);
  }
}

// ...
const reader = new ReportReader();
await report = await reader.read('report.xml');

import { readFile as readFileCb } from 'fs';
import { promisify } from 'util';

const readFile = promisify(readFileCb);

type ReportData = {
  // ..
}

interface Formatter {
  parse<T>(content: string): T;
}

class XmlFormatter implements Formatter {
  parse<T>(content: string): T {
    // XML 문자열을 T 객체로 변환
  }
}


class JsonFormatter implements Formatter {
  parse<T>(content: string): T {
    // JSON 문자열을 T 객체로 변환
  }
}

class ReportReader {
  constructor(private readonly formatter: Formatter) {
  }

  async read(path: string): Promise<ReportData> {
    const text = await readFile(path, 'UTF8');
    return this.formatter.parse<ReportData>(text);
  }
}

// ...
const reader = new ReportReader(new XmlFormatter());
await report = await reader.read('report.xml');

// 또는 json 보고서가 필요한 경우
const reader = new ReportReader(new JsonFormatter());
await report = await reader.read('report.json');

import { assert } from 'chai';

describe('AwesomeDate', () => {
  it('handles date boundaries', () => {
    let date: AwesomeDate;

    date = new AwesomeDate('1/1/2015');
    assert.equal('1/31/2015', date.addDays(30));

    date = new AwesomeDate('2/1/2016');
    assert.equal('2/29/2016', date.addDays(28));

    date = new AwesomeDate('2/1/2015');
    assert.equal('3/1/2015', date.addDays(28));
  });
});

import { assert } from 'chai';

describe('AwesomeDate', () => {
  it('handles 30-day months', () => {
    const date = new AwesomeDate('1/1/2015');
    assert.equal('1/31/2015', date.addDays(30));
  });

  it('handles leap year', () => {
    const date = new AwesomeDate('2/1/2016');
    assert.equal('2/29/2016', date.addDays(28));
  });

  it('handles non-leap year', () => {
    const date = new AwesomeDate('2/1/2015');
    assert.equal('3/1/2015', date.addDays(28));
  });
});

describe('Calendar', () => {
  it('2/29/2020', () => {
    // ...
  });

  it('throws', () => {
    // ...
  });
});

describe('Calendar', () => {
  it('should handle leap year', () => {
    // ...
  });

  it('should throw when format is invalid', () => {
    // ...
  });
});

import { get } from 'request';
import { writeFile } from 'fs';

function downloadPage(url: string, saveTo: string, callback: (error: Error, content?: string) => void) {
  get(url, (error, response) => {
    if (error) {
      callback(error);
    } else {
      writeFile(saveTo, response.body, (error) => {
        if (error) {
          callback(error);
        } else {
          callback(null, response.body);
        }
      });
    }
  });
}

downloadPage('https://en.wikipedia.org/wiki/Robert_Cecil_Martin', 'article.html', (error, content) => {
  if (error) {
    console.error(error);
  } else {
    console.log(content);
  }
});

import { get } from 'request';
import { writeFile } from 'fs';
import { promisify } from 'util';

const write = promisify(writeFile);

function downloadPage(url: string, saveTo: string): Promise<string> {
  return get(url)
    .then(response => write(saveTo, response));
}

downloadPage('https://en.wikipedia.org/wiki/Robert_Cecil_Martin', 'article.html')
  .then(content => console.log(content))
  .catch(error => console.error(error));  

import { get } from 'request';
import { writeFile } from 'fs';
import { promisify } from 'util';

const write = util.promisify(writeFile);

function downloadPage(url: string, saveTo: string): Promise<string> {
  return get(url).then(response => write(saveTo, response));
}

downloadPage('https://en.wikipedia.org/wiki/Robert_Cecil_Martin', 'article.html')
  .then(content => console.log(content))
  .catch(error => console.error(error));  

import { get } from 'request';
import { writeFile } from 'fs';
import { promisify } from 'util';

const write = promisify(writeFile);

async function downloadPage(url: string, saveTo: string): Promise<string> {
  const response = await get(url);
  await write(saveTo, response);
  return response;
}

// somewhere in an async function
try {
  const content = await downloadPage('https://en.wikipedia.org/wiki/Robert_Cecil_Martin', 'article.html');
  console.log(content);
} catch (error) {
  console.error(error);
}

function calculateTotal(items: Item[]): number {
  throw 'Not implemented.';
}

function get(): Promise<Item[]> {
  return Promise.reject('Not implemented.');
}

function calculateTotal(items: Item[]): number {
  throw new Error('Not implemented.');
}

function get(): Promise<Item[]> {
  return Promise.reject(new Error('Not implemented.'));
}

// 또는 아래와 동일합니다:

async function get(): Promise<Item[]> {
  throw new Error('Not implemented.');
}

type Result<R> = { isError: false, value: R };
type Failure<E> = { isError: true, error: E };
type Failable<R, E> = Result<R> | Failure<E>;

function calculateTotal(items: Item[]): Failable<number, 'empty'> {
  if (items.length === 0) {
    return { isError: true, error: 'empty' };
  }

  // ...
  return { isError: false, value: 42 };
}

try {
  functionThatMightThrow();
} catch (error) {
  console.log(error);
}

// 아래 예제는 훨씬 나쁩니다.

try {
  functionThatMightThrow();
} catch (error) {
  // 에러를 무시
}

import { logger } from './logging'

try {
  functionThatMightThrow();
} catch (error) {
  logger.log(error);
}

getUser()
  .then((user: User) => {
    return sendEmail(user.email, 'Welcome!');
  })
  .catch((error) => {
    console.log(error);
  });

import { logger } from './logging'

getUser()
  .then((user: User) => {
    return sendEmail(user.email, 'Welcome!');
  })
  .catch((error) => {
    logger.log(error);
  });

// 또는 async/await 구문을 사용할 수 있습니다:

try {
  const user = await getUser();
  await sendEmail(user.email, 'Welcome!');
} catch (error) {
  logger.log(error);
}

const DAYS_IN_WEEK = 7;
const daysInMonth = 30;

const songs = ['Back In Black', 'Stairway to Heaven', 'Hey Jude'];
const Artists = ['ACDC', 'Led Zeppelin', 'The Beatles'];

function eraseDatabase() {}
function restore_database() {}

type animal = { /* ... */ }
type Container = { /* ... */ }

const DAYS_IN_WEEK = 7;
const DAYS_IN_MONTH = 30;

const SONGS = ['Back In Black', 'Stairway to Heaven', 'Hey Jude'];
const ARTISTS = ['ACDC', 'Led Zeppelin', 'The Beatles'];

function eraseDatabase() {}
function restoreDatabase() {}

type Animal = { /* ... */ }
type Container = { /* ... */ }

class PerformanceReview {
  constructor(private readonly employee: Employee) {
  }

  private lookupPeers() {
    return db.lookup(this.employee.id, 'peers');
  }

  private lookupManager() {
    return db.lookup(this.employee, 'manager');
  }

  private getPeerReviews() {
    const peers = this.lookupPeers();
    // ...
  }

  review() {
    this.getPeerReviews();
    this.getManagerReview();
    this.getSelfReview();

    // ...
  }

  private getManagerReview() {
    const manager = this.lookupManager();
  }

  private getSelfReview() {
    // ...
  }
}

const review = new PerformanceReview(employee);
review.review();

class PerformanceReview {
  constructor(private readonly employee: Employee) {
  }

  review() {
    this.getPeerReviews();
    this.getManagerReview();
    this.getSelfReview();

    // ...
  }

  private getPeerReviews() {
    const peers = this.lookupPeers();
    // ...
  }

  private lookupPeers() {
    return db.lookup(this.employee.id, 'peers');
  }

  private getManagerReview() {
    const manager = this.lookupManager();
  }

  private lookupManager() {
    return db.lookup(this.employee, 'manager');
  }

  private getSelfReview() {
    // ...
  }
}

const review = new PerformanceReview(employee);
review.review();

import { TypeDefinition } from '../types/typeDefinition';
import { AttributeTypes } from '../model/attribute';
import { ApiCredentials, Adapters } from './common/api/authorization';
import fs from 'fs';
import { ConfigPlugin } from './plugins/config/configPlugin';
import { BindingScopeEnum, Container } from 'inversify';
import 'reflect-metadata';

import 'reflect-metadata';

import fs from 'fs';
import { BindingScopeEnum, Container } from 'inversify';

import { AttributeTypes } from '../model/attribute';
import { TypeDefinition } from '../types/typeDefinition';

import { ApiCredentials, Adapters } from './common/api/authorization';
import { ConfigPlugin } from './plugins/config/configPlugin';

import { UserService } from '../../../services/UserService';

import { UserService } from '@services/UserService';

// subscription이 활성화 상태인지 체크합니다.
if (subscription.endDate > Date.now) {  }

const isSubscriptionActive = subscription.endDate > Date.now;
if (isSubscriptionActive) { /* ... */ }

type User = {
  name: string;
  email: string;
  // age: number;
  // jobPosition: string;
}

type User = {
  name: string;
  email: string;
}

/**
 * 2016-12-20: 이해하지 못해서 모나드를 제거함 (RM)
 * 2016-10-01: 특별한 모나드를 사용해 개선함 (JP)
 * 2016-02-03: 타입 체킹 추가함 (LI)
 * 2015-03-14: combine 함수를 구현함 (JR)
 */
function combine(a: number, b: number): number {
  return a + b;
}