Object Oriented Programming

// generic objectclass Tag {  className: string;  id: string;  constructor(className: string, id: string) {    this.className = className;    this.id = id;  }  display() { ... }}// inheritanceclass AnchorTag extends Tag {  href: string;  constructor(className: string, id: string, href: string) {    super(className, id);    this.href = href;  }  // override  display() { ... }  // adding feature  onClick() { ... }}

// generic objectclass Tag {  className: string;  id: string;  constructor(className: string, id: string) {    this.className = className;    this.id = id;  }  display() { ... }}// inheritanceclass AnchorTag {  href: string;  tag: Tag; // composing the Tag object  constructor(className: string, id: string, href: string) {    this.tag = new Tag(className; id); // this can be improved by providing factory method that returns interface to reduce coupling.    this.href = href;  }  // use Tag display method  display() {    this.tag.display();  }  // adding feature  onClick() { ... }}

const user = (name) => {  let nameField = name;  return {    setName: (newName) => {      /*        * validate input to protect        * invalid state for nameField       */      nameField = newName;    },    getName: () => {      /*       * hide how nameField retrieved       */      return nameField;    }  }}const tom = user("tom");// tom.nameField = 123897 is now protectedconsole.log(tom.getName()) // tomtom.setName('thomas');console.log(tom.getName()) // thom

interface IUser {  setName(newName: string);  getName(): string;}class User implements IUser {  name: string  constructor(name: string) {    // validation    this.name = name;  }  setName(newName: string) {    // validation    this.name = newName;  }  getName(): string {    // hide how it was retrieved    return this.name;  }}// factory functionconst createUser = (name: string): IUser {  return new User(name);}const user = createUser('tom');// user.name error name is not defined on interface.user.setName('thom');user.getName(); // thom

interface IPlayer {  play();}// Abstracted;class Player implements IPlayer {  file: IPlayer;  constructor(f: IPlayer) {    this.file = f;  }  play() { // abstraction of play();    this.file.play();  }}// concrete classclass Mp3 implements IPlayer {  play() {    // do stuffs here.  }}// concrete classclass Mp4 implements IPlayer {  play() {    // do stuffs here  }}// factory functionconst createFile(file: string): IPlayer {  switch(file) {    case 'mp3':      return new Mp3();    case 'mp4':      return new Mp4();  }}// clientconst player = new Player(createFile('mp3'));player.play();

// consumerif (15 > 10 && 15 < 20)) {  console.log('I inside of range');}

// Abstractionconst initRange = (value) => (min, max) => value > min && value < max;const rangeOf = initRange(15);// Consumer// Abstractedif (rangeOf(10, 20)) {  console.log('I inside of range');}

interface Action {  act();}class People {  action: Action;  constructor(action: Action) {    this.action = action;  }  setAction(action: Action) {    this.action = action;  }  perform() {    this.action.act();  }}class Sing implements Action {  act() {    console.log('Singing');  }}class Dance implements Action {  act() {    console.log('Dancing');  }}const sarah = new People(new Sing())sarah.act(); // Singingsarah.setAction(new Dance());sarah.act(); // Dancing