diff --git a/src/patterns/01-abstractFactory/example.js b/src/patterns/01-abstractFactory/example.js
deleted file mode 100644
index b706559..0000000
--- a/src/patterns/01-abstractFactory/example.js
+++ /dev/null
@@ -1,66 +0,0 @@
-/*
-ComponentFactory
-createButton
-createInput
-createTable
-*/
-
-interface ComponentFactory {
-    createButton(): Button;
-    createInput(): Input;
-    createTable(): Table;
-}
-
-const darkThemeFabric = {
-    getButton() {
-        return Button
-    },
-    createInput() {
-        return <Input/>
-    },
-    createTable() {
-        return <Table/>}
-}
-const defaultThemeFabric = {
-    createButton() {
-
-    },
-    createInput() {
-
-    },
-    createTable() {}
-}
-const nativeThemeFabric = {
-    createButton() {
-
-    },
-    createInput() {
-
-    },
-    createTable() {}
-}
-
-
-function createButton(fabric: ComponentFactory) {
-    return fabric.createButton();
-}
-
-function createInput(fabric: ComponentFactory) {
-    
-}
-
-function createTable(fabric: ComponentFactory) {
-    
-}
-
-function App() {
-    return <FabricContext.Provider value={isWeb ? darkThemeFabric : defaultThemeFabric}>{...}</Provider>
-}
-
-
-function Component() {
-    const fabric = useContext(FabricContext)
-    return <div>
-        {currentFabric.createButton()}
-    </div>
-}
\ No newline at end of file
diff --git a/src/patterns/01-abstractFactory/index.js b/src/patterns/01-abstractFactory/index.js
index 6747591..b110f18 100644
--- a/src/patterns/01-abstractFactory/index.js
+++ b/src/patterns/01-abstractFactory/index.js
@@ -1,22 +1,50 @@
-export class SuccessButton {}
-export class ErrorButton {}
-export class SuccessNotification {}
-export class ErrorNotification {}
+export class SuccessButton {
+  create() {
+    return '<div class="button button__success">Button</div>'
+  }
+}
+
+export class ErrorButton {
+  create() {
+    return '<div class="button button__error">Button</div>'
+  }
+}
+
+export class SuccessNotification {
+  create() {
+    return '<div class="notify notify__success">Notification</div>'
+  }
+}
+
+export class ErrorNotification {
+  create() {
+    return '<div class="notify notify__error">Notification</div>'
+  }
+}
 
 export class SuccessControl {
   create (type = '') {
-    // todo: implement logic
+    if (type === 'notification')
+      return new SuccessNotification()
+    else
+      return new SuccessButton()
   }
 }
 
 export class ErrorControl {
   create (type = '') {
-    // todo: implement logic
+    if (type === 'notification')
+      return new ErrorNotification()
+    else
+      return new ErrorButton()
   }
 }
 
 export default class ControlsFactory {
   getFactory (factoryType = '') {
-    // todo: implement logic
+    if (factoryType === 'error')
+      return new ErrorControl()
+    else
+      return new SuccessControl()
   }
 }
diff --git a/src/patterns/02-builder/example.js b/src/patterns/02-builder/example.js
deleted file mode 100644
index 4de17e0..0000000
--- a/src/patterns/02-builder/example.js
+++ /dev/null
@@ -1,29 +0,0 @@
-const playerConfig = {
-    config: {},
-
-    addAdConfig() {
-
-    },
-
-    addDrmConfig({url, type}) {
-        this.config.drmUrl = url;
-        this.config.drmType = type;
-    },
-
-    addTrackerConfig() {
-
-    },
-
-    addDeviceConfig() {
-
-    },
-}
-
-
-const config = new PlayerConfig('theBestFilmUrl');
-
-if (isDrmNeeded) {
-    config.addDrmConfig({type: 'widevine', url: ''});
-}
-
-
diff --git a/src/patterns/02-builder/index.js b/src/patterns/02-builder/index.js
index 8d7f02c..7ad53d1 100644
--- a/src/patterns/02-builder/index.js
+++ b/src/patterns/02-builder/index.js
@@ -1,17 +1,21 @@
 export default class RequestBuilder {
   constructor(url = '') {
-    this.url = new URL(url);
+    this.url = new URL(url)
   }
 
   addPagination (start, end) {
-    // todo: implement logic
+    this.url.searchParams.set('start', start)
+    this.url.searchParams.set('end', end)
   }
 
   addSort (sort, order) {
-    // todo: implement logic
+    this.url.searchParams.set('sort', sort)
+    this.url.searchParams.set('order', order)
   }
 
   addFilter (filter, filterLte, filterGte) {
-    // todo: implement logic
+    this.url.searchParams.set('filter', filter)
+    this.url.searchParams.set('filter_lte', filterLte)
+    this.url.searchParams.set('filter_gte', filterGte)
   }
 }
diff --git a/src/patterns/03-factoryMethod/example.js b/src/patterns/03-factoryMethod/example.js
deleted file mode 100644
index 644912e..0000000
--- a/src/patterns/03-factoryMethod/example.js
+++ /dev/null
@@ -1,37 +0,0 @@
-
-class FabricNode {
-    draw() {
-        return <FabricNode/>
-    }
-}
-
-class StorageNode {
-    draw() {
-        return <StorageNode/>
-    }
-}
-
-const config = {
-    fabric: {
-
-    },
-    storage: {
-
-    },
-    region: {
-        fabric: {},
-        storage: {},
-        town: {
-            fabric: {},
-            storage: {},
-        }
-    }
-}
-
-
-function paint(node) {
-    const view = node.draw();
-
-
-}
-
diff --git a/src/patterns/03-factoryMethod/index.js b/src/patterns/03-factoryMethod/index.js
index a299f29..0e561d7 100644
--- a/src/patterns/03-factoryMethod/index.js
+++ b/src/patterns/03-factoryMethod/index.js
@@ -2,22 +2,36 @@ class Input {
   element = {};
 
   create () {
-    // Abstract method
+    return this.element
   }
 }
 
 export class TextInput extends Input {
-  // todo: implement logic
+  create() {
+    this.element.type = 'text'
+    super.create()
+  }
 }
 
 export class NumberInput extends Input {
-  // todo: implement logic
+  create() {
+    this.element.type = 'number'
+    super.create()
+  }
 }
 
 export class EmailInput extends Input {
-  // todo: implement logic
+  create() {
+    this.element.type = 'email'
+    super.create()
+  }
 }
 
 export const inputFactory = (type = '') => {
-  // todo: implement logic
+  if (type === 'number')
+    return new NumberInput()
+  else if (type === 'email')
+    return new EmailInput()
+
+  return new TextInput()
 };
diff --git a/src/patterns/04-prototype/examples.js b/src/patterns/04-prototype/examples.js
deleted file mode 100644
index 662a254..0000000
--- a/src/patterns/04-prototype/examples.js
+++ /dev/null
@@ -1,20 +0,0 @@
-const storageNode = {
-    id: 'asdasdasdas',
-    level: 100,
-    quality: {
-        a: 1,
-        b: 2,
-        c: 3,
-    },
-    
-
-    clone() {
-        return {
-            ...storageNode,
-            quality: {
-
-            },
-            id: nanoid(),
-        }
-    }
-}
\ No newline at end of file
diff --git a/src/patterns/04-prototype/index.js b/src/patterns/04-prototype/index.js
index 208269d..eab870d 100644
--- a/src/patterns/04-prototype/index.js
+++ b/src/patterns/04-prototype/index.js
@@ -1,20 +1,27 @@
 class Monster {
-  // todo: implement logic
+  constructor(settings = {}) {
+    this.settings = settings
+  }
 }
 
 export default class Location {
-  monsters = [];
+  monsters = []
 
   constructor(name = '', monstersCount = 0, monstersSettings = {}) {
-    this.name = name;
-    // todo: implement logic
+    this.name = name
+    this.monstersCount = monstersCount
+    this.monstersSettings = monstersSettings
+
+    this.initMonsters()
   }
 
   initMonsters () {
-    // todo: implement logic
+    for (let i = 0; i < this.monstersCount; i++) {
+      this.monsters.push(new Monster(this.monstersSettings));
+    }
   }
 
   clone () {
-    // todo: implement logic
+    return { ...new Location() }
   }
 }
diff --git a/src/patterns/05-singleton/example.js b/src/patterns/05-singleton/example.js
deleted file mode 100644
index 2630fb9..0000000
--- a/src/patterns/05-singleton/example.js
+++ /dev/null
@@ -1,19 +0,0 @@
-const player = {
-    play() {}
-}
-
-Object.freeze(player);
-
-export {player};
-
-export default class Singleton {
-    static #instance;
-  
-    constructor() {
-      if (Singleton.#instance) {
-        return Singleton.#instance;
-      }
-  
-      Singleton.#instance = this;
-    }
-  }
\ No newline at end of file
diff --git a/src/patterns/05-singleton/index.js b/src/patterns/05-singleton/index.js
index 0927bab..84d9ee5 100644
--- a/src/patterns/05-singleton/index.js
+++ b/src/patterns/05-singleton/index.js
@@ -1,5 +1,11 @@
 export default class Singleton {
+  static #instance;
+
   constructor() {
-    // todo: implement logic
+    if (Singleton.#instance) {
+      return Singleton.#instance;
+    }
+
+    Singleton.#instance = this;
   }
 }
diff --git a/src/patterns/05-singleton/index.spec.js b/src/patterns/05-singleton/index.spec.js
index a0580ed..7b6ad81 100644
--- a/src/patterns/05-singleton/index.spec.js
+++ b/src/patterns/05-singleton/index.spec.js
@@ -2,6 +2,6 @@ import Singleton from './index.js';
 
 describe('patterns/singleton', () => {
   it('should return the same instance', () => {
-    expect(new Singleton() === new Singleton()). toBeTruthy();
+    expect(new Singleton() === new Singleton()).toBeTruthy();
   });
 });
diff --git a/src/patterns/06-adapter/index.js b/src/patterns/06-adapter/index.js
index a61bc05..7c985e5 100644
--- a/src/patterns/06-adapter/index.js
+++ b/src/patterns/06-adapter/index.js
@@ -1,23 +1,24 @@
 export const getArea = shape => {
-  return shape.width * shape.height;
+  return shape.width * shape.height
 };
 
 export class Square {
   constructor(size) {
-    this.size = size;
+    this.size = size
   }
 }
 
 export class Rectangle {
   constructor(width, height) {
-    this.width = width;
-    this.height = height;
+    this.width = width
+    this.height = height
   }
 }
 
 export class Adapter {
   constructor(shape) {
-    // todo: add implementation
+    this.width = shape.width ?? shape.size
+    this.height = shape.height ?? shape.size
   }
 }
 
diff --git a/src/patterns/07-bridge/example.js b/src/patterns/07-bridge/example.js
deleted file mode 100644
index 83122ad..0000000
--- a/src/patterns/07-bridge/example.js
+++ /dev/null
@@ -1,32 +0,0 @@
-interface Tv {
-    getVolume(): number;
-    setVolume(): number;
-    //...
-}
-
-class Lg {
-    getVolume() {};
-    setVolume() {};
-}
-
-class Samsung {
-    getVolume() {};
-    setVolume() {};
-}
-
-class Sony {
-    getVolume() {};
-    setVolume() {};
-}
-
-class Remote {
-    device: Tv;
-
-    setDevice(device) {
-        this.device = device;
-    }
-
-    changeVolumeByStep(step = 10) {
-        this.device.setVolume(this.device.getVolume() + step)
-    }
-}
\ No newline at end of file
diff --git a/src/patterns/07-bridge/index.js b/src/patterns/07-bridge/index.js
index 0c5419e..097b4de 100644
--- a/src/patterns/07-bridge/index.js
+++ b/src/patterns/07-bridge/index.js
@@ -1,21 +1,22 @@
 export class RedColorsPallet {
-  constructor () {
+  constructor() {
     this.color = 'red';
   }
 }
 
 export class GreenColorsPallet {
-  constructor () {
+  constructor() {
     this.color = 'green';
   }
 }
 
 export class Notification {
-  constructor () {
-    // todo: add implementation
+  constructor(name, pallet) {
+    this.name = name;
+    this.colorsPallet = pallet;
   }
 
-  toString () {
+  toString() {
     return `This is ${this.name} notification with ${this.colorsPallet.color} colors pallet`;
   }
 }
diff --git a/src/patterns/08-composite/example.js b/src/patterns/08-composite/example.js
deleted file mode 100644
index fd4a663..0000000
--- a/src/patterns/08-composite/example.js
+++ /dev/null
@@ -1,44 +0,0 @@
-class Fabric {
-    items;
-    draw() {
-        // logic
-        this.items.forEach(item => item.draw)
-    }
-}
-
-class Node {
-    draw() {
-        //logic
-    }
-}
-
-class Storage {
-    items;
-    draw() {
-        // logic
-        this.items.forEach(item => item.draw)
-    }
-}
-
-class Graph {
-    items;
-    draw() {
-        this.items.forEach(item => item.draw)
-    }
-}
-
-const node = new Node();
-const node1 = new Node();
-const node2 = new Node();
-const node3 = new Node();
-const node4 = new Node();
-const storage = new Storage();
-const fabric = new Fabric();
-
-const graph = new Graph();
-
-graph.items = [storage, fabric, node];
-storage.items = [node1, node2];
-fabric.items = [node3, node4]
-
-graph.draw();
\ No newline at end of file
diff --git a/src/patterns/08-composite/index.js b/src/patterns/08-composite/index.js
index b41c387..b007758 100644
--- a/src/patterns/08-composite/index.js
+++ b/src/patterns/08-composite/index.js
@@ -3,8 +3,8 @@ export class Child {
     this.value = value;
   }
 
-  getSum () {
-    // todo: add implementation
+  getSum() {
+    return this.value;
   }
 }
 
@@ -13,8 +13,8 @@ export class Parent {
     this.values = values;
   }
 
-  getSum () {
-    // todo: add implementation
+  getSum() {
+    return this.values.reduce((acc, value) => acc + value.getSum(), 0)
   }
 }
 
diff --git a/src/patterns/09-decorator/index.js b/src/patterns/09-decorator/index.js
index 0c1ee33..cddddf2 100644
--- a/src/patterns/09-decorator/index.js
+++ b/src/patterns/09-decorator/index.js
@@ -1,20 +1,40 @@
-export class Milk {
-  price = 2;
+class Additional {
+  price
 
-  // todo: add implementation
+  constructor(coffee = null) {
+    if (this.constructor.name === 'Additional') {
+      throw new Error(`${this.constructor.name}: can not create instance of abstract class`);
+    }
+
+    this.coffePrice = coffee ? coffee.getPrice() : 0
+  }
+
+  getPrice () {
+    return this.price + this.coffePrice
+  }
+}
+
+export class Milk extends Additional {
+  price = 2
+
+  getPrice () {
+    return super.getPrice()
+  }
 }
 
-export class Sugar {
-  price = 1;
+export class Sugar extends Additional {
+  price = 1
 
-  // todo: add implementation
+  getPrice () {
+    return super.getPrice()
+  }
 }
 
 export class Coffee {
-  price = 5;
+  price = 5
 
   getPrice () {
-    return this.price;
+    return this.price
   }
 }
 
diff --git a/src/patterns/10-facade/example.js b/src/patterns/10-facade/example.js
deleted file mode 100644
index 20d39ab..0000000
--- a/src/patterns/10-facade/example.js
+++ /dev/null
@@ -1,29 +0,0 @@
-const facade = {
-    player,
-    tracker,
-    logger,
-    adPlanner,
-
-    play() {
-        this.adPlanner.playAd();
-        this.tracker.sendTrack();
-        this.player.play();
-    },
-
-    upVolume() {
-       if(this.player.isMute()) {
-        this.player.unmute();
-       }
-
-       this.player.setVolume(this.player.currentVolume + 1)
-    },
-
-    downVolume() {
-
-    }
-}
-
-facade.play();
-facade.upVolume();
-
-
diff --git a/src/patterns/10-facade/index.js b/src/patterns/10-facade/index.js
index 0f6321d..5c19e42 100644
--- a/src/patterns/10-facade/index.js
+++ b/src/patterns/10-facade/index.js
@@ -1,6 +1,11 @@
 export class Game {
-  start () {
-    // todo: add implementation
+  start() {
+    this.hero = new Hero('Barbarian');
+    this.location = new Location('darkForest');
+
+    this.location.addMonster(new Monster('demon'));
+    this.location.addMonster(new Monster('demon'));
+    this.location.addMonster(new Monster('undead'));
   }
 }
 
@@ -11,7 +16,7 @@ class Location {
     this.name = name;
   }
 
-  addMonster (monster = {}) {
+  addMonster(monster = {}) {
     this.monsters.push(monster);
   }
 }
diff --git a/src/patterns/11-flyweight/example.js b/src/patterns/11-flyweight/example.js
deleted file mode 100644
index 5eb63f7..0000000
--- a/src/patterns/11-flyweight/example.js
+++ /dev/null
@@ -1,27 +0,0 @@
-const part = {
-    characteristics: characteristics1,
-    x: 0,
-    y: 0,
-}
-
-const par1 = {
-    characteristics: characteristics1,
-    x: 0,
-    y: 0,
-}
-
-const characteristics1 =  {
-    color: 'red',
-    size: 'l',
-    speed: '',
-}
-const characteristics2 =  {
-    color: 'blue',
-    size: 'm',
-    speed: '',
-}
-const characteristics3 =  {
-    color: 'green',
-    size: 's',
-    speed: '',
-}
\ No newline at end of file
diff --git a/src/patterns/11-flyweight/index.js b/src/patterns/11-flyweight/index.js
index a44aa44..436272a 100644
--- a/src/patterns/11-flyweight/index.js
+++ b/src/patterns/11-flyweight/index.js
@@ -1,18 +1,27 @@
 class Flyweight {
-  // todo: add implementation
+  constructor(info) {
+    this.info = info
+  }
 }
 
 export class ProductsStore {
-  flyweights = {};
-  products = [];
+  flyweights = {}
+  products = []
 
   addProduct (productData = {}) {
-    const productFlyweight = this.getOrCreateFlyweight(productData.info);
-
-    // todo: add implementation
+    const productFlyweight = this.getOrCreateFlyweight(productData.info)
+    this.products.push({
+      ...productData,
+      info: productFlyweight
+    })
   }
 
   getOrCreateFlyweight (info = {}) {
-    // todo: add implementation
+    const { name, color } = info
+    if (!this.flyweights[name + '_' + color]) {
+      this.flyweights[name + '_' + color] =
+          new Flyweight(info)
+    }
+    return this.flyweights[name + '_' + color]
   }
 }
diff --git a/src/patterns/12-proxy/example.js b/src/patterns/12-proxy/example.js
deleted file mode 100644
index 372b45c..0000000
--- a/src/patterns/12-proxy/example.js
+++ /dev/null
@@ -1,27 +0,0 @@
-// const player = {
-//     play() {
-//         const film = FilmGetterProxy.getFilm()
-
-        
-//     }
-// }
-
-const FilmGetterProxy = {
-    getFilm() {
-        if (Cache.hasFilm()) {
-            return Cache.getFilm();
-        }
-
-        return Loader.loadFilm();
-    }
-}
-
-const Cache = {
-
-}
-
-const Loader = {
-
-}
-
-FilmGetterProxy.getFilm();
\ No newline at end of file
diff --git a/src/patterns/12-proxy/index.js b/src/patterns/12-proxy/index.js
index 0672507..cdc4e12 100644
--- a/src/patterns/12-proxy/index.js
+++ b/src/patterns/12-proxy/index.js
@@ -10,14 +10,14 @@ export class User {
 }
 
 export class ProxyUser {
-  rights = [];
-
-  constructor() {
-    // todo: add implementation
+  constructor(user) {
+    this.user = user
   }
 
   write () {
-    // todo: add implementation
+    if (this.user.rights.includes('admin'))
+      return this.user.write()
+    else return 'user does not have permissions to write'
   }
 }
 
diff --git a/src/patterns/13-chainOfResponsibility/example.js b/src/patterns/13-chainOfResponsibility/example.js
deleted file mode 100644
index 6dcea78..0000000
--- a/src/patterns/13-chainOfResponsibility/example.js
+++ /dev/null
@@ -1,54 +0,0 @@
-// action -> m -> m -> m -> reducer
-
-
-function m(next, action) {
-    if (validate(action)) {
-        next()
-    }
-}
-
-
-const AuthorizationFilter = {
-    next,
-    setNext(next) {
-        this.next = next
-    },
-
-    handle() {
-        //logic
-        if (success) {
-            this.next.handle();
-        }
-    }
-}
-const RoleFilter = {
-    next,
-    setNext(next) {
-        this.next = next
-    },
-
-    handle() {
-        //logic
-        if (success) {
-            this.next.handle();
-        }
-    }
-}
-const LocationFilter = {
-    next,
-    setNext(next) {
-        this.next = next
-    },
-
-    handle() {
-        //logic
-        if (success) {
-            this.next.handle();
-        }
-    }
-}
-
-AuthorizationFilter.setNext(RoleFilter)
-RoleFilter.setNext(LocationFilter);
-
-AuthorizationFilter.handle(request);
\ No newline at end of file
diff --git a/src/patterns/13-chainOfResponsibility/index.js b/src/patterns/13-chainOfResponsibility/index.js
index d0af96a..aa5d6f3 100644
--- a/src/patterns/13-chainOfResponsibility/index.js
+++ b/src/patterns/13-chainOfResponsibility/index.js
@@ -1,51 +1,58 @@
 class Handler {
-  name = '';
-  regExp = /./;
+  name = ''
+  regExp = /./
+  nextHandler = null
 
   setNext (handler) {
-    // todo: implement
+    this.nextHandler = handler
+    return this.nextHandler
   }
 
-  next (data) {
-    // todo: implement
+  next(data) {
+    if (this.nextHandler)
+      return this.nextHandler.validate(data)
   }
 
   validate (data) {
-    // todo: implement
+    if (this.regExp.test(data)) {
+      return this.next(data)
+    }
+
+    return `Validation rule "${this.name}" didn't pass for string "${data}"`
   }
 }
 
 class MinLengthHandler extends Handler {
-  name = 'min-length';
-  regExp = /.{5}/;
+  name = 'min-length'
+  regExp = /.{5}/
 }
 
 class NumbersHandler extends Handler {
-  name = 'numbers';
-  regExp = /[0-9]/;
+  name = 'numbers'
+  regExp = /[0-9]/
 }
 
 class LettersHandler extends Handler {
-  name = 'letter';
-  regExp = /[a-z]/i;
+  name = 'letter'
+  regExp = /[a-z]/i
 }
 
 class CapitalLettersHandler extends Handler {
-  name = 'capital-letters';
-  regExp = /[A-Z]/;
+  name = 'capital-letters'
+  regExp = /[A-Z]/
 }
 
 class SpecialCharsHandler extends Handler {
-  name = 'special-chars';
-  regExp = /[`!@#$%^&*()_+\-=\[\]{};':"\\|,.<>\/?~]/;
+  name = 'special-chars'
+  regExp = /[`!@#$%^&*()_+\-=\[\]{};':"\\|,.<>\/?~]/
 }
 
-const chainOfResponsibility = new MinLengthHandler();
+const chainOfResponsibility = new MinLengthHandler()
 
 chainOfResponsibility
   .setNext(new NumbersHandler())
   .setNext(new LettersHandler())
   .setNext(new CapitalLettersHandler())
-  .setNext(new SpecialCharsHandler());
+  .setNext(new SpecialCharsHandler())
 
-export default chainOfResponsibility;
+export default chainOfResponsibility
diff --git a/src/patterns/14-command/example.js b/src/patterns/14-command/example.js
deleted file mode 100644
index b4b1ed6..0000000
--- a/src/patterns/14-command/example.js
+++ /dev/null
@@ -1,37 +0,0 @@
-class Editor {
-    history = [];
-    hasResources = true;
-    queue = [];
-
-    executeCommand(command) {
-        if (this.hasResources) {
-            command.execute()
-            this.history.push(command);
-        } else {
-            this.queue.push(command);
-        }
-    }
-
-    undo() {
-        const lastCommand = this.history[this.history.length - 1];
-        lastCommand.undo()
-        this.history.length = this.history.length - 1;
-    }
-}
-
-class Command {
-    editor;
-    undo() {
-
-    }
-    execute(){
-
-    }
-}
-
-class CopyCommand {
-    editor;
-    execute() {
-
-    }
-}
\ No newline at end of file
diff --git a/src/patterns/14-command/index.js b/src/patterns/14-command/index.js
index 2282d95..da72285 100644
--- a/src/patterns/14-command/index.js
+++ b/src/patterns/14-command/index.js
@@ -1,12 +1,20 @@
 export class NextPage {
+  constructor(pagination) {
+    this.pagination = pagination
+  }
+
   execute () {
-    // todo: add implementation
+    this.pagination.nextPage()
   }
 }
 
 export class PrevPage {
+  constructor(pagination) {
+    this.pagination = pagination
+  }
+
   execute () {
-    // todo: add implementation
+    this.pagination.prevPage()
   }
 }
 
@@ -14,20 +22,20 @@ export class Pagination {
   currentPage = 1;
 
   nextPage () {
-    return this.currentPage += 1;
+    return this.currentPage += 1
   }
 
   prevPage () {
-    return this.currentPage -= 1;
+    return this.currentPage -= 1
   }
 }
 
 export class Button {
   constructor (command) {
-    // todo: add implementation
+    this.command = command
   }
 
   click () {
-    // todo: add implementation
+    this.command.execute()
   }
 }
diff --git a/src/patterns/15-iterator/example.js b/src/patterns/15-iterator/example.js
deleted file mode 100644
index e2a3ee5..0000000
--- a/src/patterns/15-iterator/example.js
+++ /dev/null
@@ -1,19 +0,0 @@
-const MyCustomTree = {
-    root = {
-        children: [...],
-    },
-
-    iterator = {
-        currentIndex = 0,
-        getNext() {
-            return
-        },
-        hasMore() {
-
-        }
-    }
-}
-
-MyCustomTree.getNext();
-MyCustomTree.getNext();
-MyCustomTree.iterator.hasMore();
diff --git a/src/patterns/15-iterator/index.js b/src/patterns/15-iterator/index.js
index 360fbc6..7d8f061 100644
--- a/src/patterns/15-iterator/index.js
+++ b/src/patterns/15-iterator/index.js
@@ -5,11 +5,15 @@ export class Range {
   }
 
   forEach (callback) {
-    // todo: add implementation
+    return this.getRange().forEach(x => callback(x))
   }
 
   getRange () {
-    // todo: add implementation
+    const rangeArr = []
+    for (let i = this.start; i <= this.end; i++) {
+      rangeArr.push(i)
+    }
+    return rangeArr
   }
 }
 
diff --git a/src/patterns/15-iterator/index.spec.js b/src/patterns/15-iterator/index.spec.js
index 39aba9a..5767e77 100644
--- a/src/patterns/15-iterator/index.spec.js
+++ b/src/patterns/15-iterator/index.spec.js
@@ -1,9 +1,20 @@
-import {Range} from './index.js';
+import { Range } from './index.js'
 
 describe('patterns/iterator', () => {
   it('should be able to return the range of numbers', () => {
-    expect(new Range(1, 3).getRange()).toEqual([1, 2, 3]);
-    expect(new Range(9, 15).getRange()).toEqual([9, 10, 11, 12, 13, 14, 15]);
+    expect(new Range(1, 3).getRange()).toEqual([1, 2, 3])
+    expect(new Range(9, 15).getRange()).toEqual([9, 10, 11, 12, 13, 14, 15])
+  });
+
+  it('should be able to call the callback function for each item of the range array', () => {
+    const cb = jest.fn()
+    const range = new Range(2, 4)
+
+    range.forEach(cb)
+
+    expect(cb).toHaveBeenCalledWith(2)
+    expect(cb).toHaveBeenCalledWith(3)
+    expect(cb).toHaveBeenCalledWith(4)
   });
 });
 
diff --git a/src/patterns/16-mediator/example.js b/src/patterns/16-mediator/example.js
deleted file mode 100644
index a43181e..0000000
--- a/src/patterns/16-mediator/example.js
+++ /dev/null
@@ -1,29 +0,0 @@
-const store = {
-    dispatch(type, payload) {
-
-    }
-}
-
-
-function Card() {
-
-    return <div>
-        <button onClick={() => store.dispatch('buy', '123123')}></button>
-    </div>
-}
-
-function Cart() {
-
-    return <div>
-        <ul>
-            <li>pizza <button onClick={() => store.dispatch('remove', '123123')}></button></li>
-        </ul>
-    </div>
-}
-
-function Modal() {
-
-    return <div>
-    <li>pizza <button onClick={() => store.dispatch('replace', '123123')}></button></li>
-    </div>
-}
\ No newline at end of file
diff --git a/src/patterns/16-mediator/imgs/friends.png b/src/patterns/16-mediator/imgs/friends.png
deleted file mode 100644
index ddb6da5..0000000
Binary files a/src/patterns/16-mediator/imgs/friends.png and /dev/null differ
diff --git a/src/patterns/16-mediator/index.js b/src/patterns/16-mediator/index.js
index 5d7339a..f6e6421 100644
--- a/src/patterns/16-mediator/index.js
+++ b/src/patterns/16-mediator/index.js
@@ -7,7 +7,7 @@ export class BillSharing {
   }
 
   addParticipant (participant) {
-    // todo: add implementation
+    this.participants.push(participant)
   }
 
   getPaymentAmount() {
@@ -19,11 +19,14 @@ export class BillSharing {
   }
 
   share () {
-    // todo: add implementation
+    this.participants.forEach(p => p.pay())
   }
 
   borrow (amount = 0) {
-    // todo: add implementation
+    const participantsWithCash = this.participants.filter(p => p.cash)
+    participantsWithCash.forEach(p => {
+      p.borrow(amount / participantsWithCash.length)
+    })
   }
 }
 
@@ -35,10 +38,20 @@ export class User {
   }
 
   pay () {
-    // todo: add implementation
+    const amount = this.billSharing.getPaymentAmount();
+    if (this.cash >= amount) {
+      this.billSharing.pay(amount)
+      this.cash -= amount
+    } else {
+      this.billSharing.pay(this.cash)
+      const diff = amount - this.cash
+      this.cash = 0;
+      this.billSharing.borrow(diff)
+    }
   }
 
   borrow (amount = 0) {
-    // todo: add implementation
+    this.billSharing.pay(amount)
+    this.cash -= amount
   }
 }
diff --git a/src/patterns/17-memento/example.js b/src/patterns/17-memento/example.js
deleted file mode 100644
index 64f56d5..0000000
--- a/src/patterns/17-memento/example.js
+++ /dev/null
@@ -1,15 +0,0 @@
-const Origin = {
-    state: { },
-
-    save() {
-
-    },
-
-    restore(snapshot) {
-
-    }
-}
-
-const snapshot = Origin.save();
-
-Origin.restore(snapshot);
\ No newline at end of file
diff --git a/src/patterns/17-memento/index.js b/src/patterns/17-memento/index.js
index 0233005..cff7221 100644
--- a/src/patterns/17-memento/index.js
+++ b/src/patterns/17-memento/index.js
@@ -1,13 +1,19 @@
-export class Memento {
-  // todo: add implementation
+class Memento {
+  constructor(state) {
+    this.state = state
+  }
+
+  getState() {
+    return this.state
+  }
 }
 
 export class History {
-  // todo: add implementation
+  snapshots = []
 }
 
 export class Hero {
-  #name = '';
+  #name = ''
 
   #state = {
     level: 1,
@@ -15,27 +21,32 @@ export class Hero {
   };
 
   constructor(name = '', history = {}) {
-    this.#name = name;
-    this.history = history;
+    this.#name = name
+    this.history = history
   }
 
   get state () {
-    return this.#state;
+    return this.#state
   }
 
   addSkill (skill) {
-    this.#state.skills.push(skill);
+    this.#state.skills.push(skill)
   }
 
   increaseLevel () {
-    this.#state.level += 1;
+    this.#state.level += 1
   }
 
   load (snapshot = {}) {
-    // todo: add implementation
+    this.#state = snapshot.getState()
   }
 
   save () {
-    // todo: add implementation
+    return new Memento({
+      ...this.state,
+      skills: [...this.state.skills]
+    })
   }
 }
+
+
diff --git a/src/patterns/18-observer/example.js b/src/patterns/18-observer/example.js
deleted file mode 100644
index ad9c8eb..0000000
--- a/src/patterns/18-observer/example.js
+++ /dev/null
@@ -1,19 +0,0 @@
-const store = {
-    subscribers: new Map(),
-
-    subscribe(callback) {
-        this.subscribers.set(callback, callback);
-
-        return () => this.subscribers.delete(callback);
-    },
-
-    notify() {
-        this.subscribers.forEach(callback => callback());
-    }
-}
-
-const unsubscribe = store.subscribe('1', () => console.log('storeChanged'));
-store.subscribe('2', () => console.log('storeChanged'));
-store.subscribe('3', () => console.log('storeChanged'));
-store.subscribe('4', () => console.log('storeChanged'));
-store.subscribe('5', () => console.log('storeChanged'));
\ No newline at end of file
diff --git a/src/patterns/18-observer/index.js b/src/patterns/18-observer/index.js
index 6474671..1a638de 100644
--- a/src/patterns/18-observer/index.js
+++ b/src/patterns/18-observer/index.js
@@ -1,23 +1,23 @@
 export class NewsChannel {
-  users = [];
+  users = []
 
   subscribe (user) {
-    // todo: add implementation
+    this.users.push(user)
   }
 
   notify (message = '') {
-    // todo: add implementation
+    this.users.forEach(user => user.receiveMessage(message))
   }
 }
 
 export class User {
-  messagesHistory = [];
+  messagesHistory = []
 
   constructor(name) {
-    this.name = name;
+    this.name = name
   }
 
   receiveMessage (message = '') {
-    // todo: add implementation
+    this.messagesHistory.push(message)
   }
 }
diff --git a/src/patterns/19-state/example.js b/src/patterns/19-state/example.js
deleted file mode 100644
index fda1904..0000000
--- a/src/patterns/19-state/example.js
+++ /dev/null
@@ -1,33 +0,0 @@
-const playerFacade = {
-    player: {
-
-    },
-    state: pause,
-
-    toggle() {
-        const state = this.state.toggle(this.player);
-
-        if (state) {
-            this.state = state
-        }
-    }
-}
-
-const playing = {
-    toggle(player) {
-        player.pause();
-        return pause;
-    }
-}
-const pause = {
-    toggle(player) {
-        player.play();
-        return playing;
-    }
-}
-const buffering = {
-    player,
-    toggle(player) {
-        // player.play();
-    }
-}
\ No newline at end of file
diff --git a/src/patterns/19-state/imgs/lock.png b/src/patterns/19-state/imgs/lock.png
deleted file mode 100644
index d2d9925..0000000
Binary files a/src/patterns/19-state/imgs/lock.png and /dev/null differ
diff --git a/src/patterns/19-state/index.js b/src/patterns/19-state/index.js
index 4d1d588..b7316d0 100644
--- a/src/patterns/19-state/index.js
+++ b/src/patterns/19-state/index.js
@@ -1,46 +1,34 @@
-// todo: make refactoring, use State pattern
-class OldDigitalLock {
-  state = {
-    status: "locked",
-    key: ""
-  };
+class Locked {
+  status = 'locked'
 
-  constructor(key = '') {
-    this.state.key = key;
+  constructor(key) {
+    this.key = key
   }
 
-  toggle (combination = '') {
-    if (this.state.status === "locked") {
-      if (combination === this.state.key) {
-        this.state.status = "unlocked";
-      }
-      return;
-    }
-
-    if (this.state.status === "unlocked") {
-      if (combination) {
-        this.state.key = combination;
-      }
-
-      this.state.status = "locked";
+  toggle(key = "") {
+    if (key === this.key) {
+      return new Unlocked()
     }
   }
 }
 
-class Locked {
-  // todo: add implementation
-}
-
 class Unlocked {
-  // todo: add implementation
+  status = 'unlocked'
+
+  toggle(key = "") {
+    if (key) {
+      return new Locked(key)
+    }
+  }
 }
 
 export class DigitalLock {
   constructor(key = "") {
-    // todo: add implementation
+    this.state = new Locked(key)
   }
 
-  toggle (combination = '') {
-    // todo: add implementation
+  toggle (key = '') {
+    const newState = this.state.toggle(key)
+    this.state = newState ? newState : new Locked(key)
   }
 }
diff --git a/src/patterns/19-state/readme.md b/src/patterns/19-state/readme.md
index 020a456..26d3504 100644
--- a/src/patterns/19-state/readme.md
+++ b/src/patterns/19-state/readme.md
@@ -12,8 +12,6 @@
 Данный класс работает по аналогии с кодовым замком, к-й часто можно встретить
 на дверцах шкафчиков в гардеробах или на цепочках для паркинга велосипедов.
 
-![](/assets/lock.png)
-
 Ввод верной комбинации открывает замок и переводит его в состояние "unlock",
 повторный ввод комбинации в состоянии "unlock", позволяет задать новую 
 комбинацию для открытия замка.
diff --git a/src/patterns/20-strategy/example.js b/src/patterns/20-strategy/example.js
deleted file mode 100644
index cc59d8a..0000000
--- a/src/patterns/20-strategy/example.js
+++ /dev/null
@@ -1,24 +0,0 @@
-const Table = {
-    filter,
-    sort,
-
-    sortBy(columnName) {
-        this.sort();
-    },
-
-    filterBy(value) {
-        this.filter();
-    }
-}
-
-function sort(columnName, items) {
-
-}
-function sort2(columnName, items) {
-
-}
-function sort3(columnName, items) {
-
-}
-
-Table.sort = sort3;
\ No newline at end of file
diff --git a/src/patterns/20-strategy/index.js b/src/patterns/20-strategy/index.js
index 1daaf22..6b8c31f 100644
--- a/src/patterns/20-strategy/index.js
+++ b/src/patterns/20-strategy/index.js
@@ -1,40 +1,49 @@
-export class Club {
-  speed = 0.5;
-  damage = 20;
+class Weapon {
+  speed = 0
+  damage = 0
+
   attack (monster) {
     return this.damage * this.speed - monster.armor;
   }
 }
 
-export class Sword {
-  speed = 1;
-  damage = 15;
+export class Club extends Weapon {
+  speed = 0.5
+  damage = 20
+  attack (monster) {
+    return super.attack(monster)
+  }
+}
+
+export class Sword extends Weapon {
+  speed = 1
+  damage = 15
   attack (monster) {
-    // todo: add implementation
+    return super.attack(monster)
   }
 }
 
-export class MagicWand {
-  speed = 2;
-  damage = 8;
+export class MagicWand extends Weapon {
+  speed = 2
+  damage = 8
   attack (monster) {
-    // todo: add implementation
+    return super.attack(monster)
   }
 }
 
 export class Hero {
-  constructor(name) {
-    this.name = name;
-    // todo: add implementation
+  constructor(name, weapon) {
+    this.name = name
+    this.weapon = weapon
   }
 
   hit (monster) {
-    // todo: add implementation
+    return this.weapon.attack(monster)
   }
 }
 
 export class Monster {
   constructor(armor = 0) {
-    this.armor = armor;
+    this.armor = armor
   }
 }
diff --git a/src/patterns/21-templateMethod/example.js b/src/patterns/21-templateMethod/example.js
deleted file mode 100644
index 5f506e5..0000000
--- a/src/patterns/21-templateMethod/example.js
+++ /dev/null
@@ -1,36 +0,0 @@
-class Node {
-    draw() {
-        this.calculateSize();
-        this.formatText();
-        this.drawChildren();
-    };
-
-    calculateSize(){
-        throw new Error('implement');
-    };
-    formatText(){
-        throw new Error('implement');};
-    drawChildren(){
-        throw new Error('implement');};
-}
-
-
-class FabricNode extends Node {
-     calculateSize() {};
-     formatText() {};
-     drawChildren() {};
-}
-
-class StorageNode extends Node {
-     calculateSize() {};
-     formatText() {};
-     drawChildren() {};
-}
-
-const fabric = new FabricNode();
-
-function draw(rootNode) {
-    rootNode.draw();
-}
-
-draw(fabric);
\ No newline at end of file
diff --git a/src/patterns/21-templateMethod/index.js b/src/patterns/21-templateMethod/index.js
index 36fadeb..ca3fee1 100644
--- a/src/patterns/21-templateMethod/index.js
+++ b/src/patterns/21-templateMethod/index.js
@@ -1,66 +1,55 @@
 class HotDrinksPot {
-  // todo: add implementation
-}
-
-// todo: make refactoring via template method pattern
-export class TeaPot {
-  algorithmSteps = {};
+  algorithmSteps = {}
 
   constructor() {
-    this.prepareRecipe();
+    this.prepareRecipe()
   }
 
   prepareRecipe () {
-    this.boilWater();
-    this.brewTea();
-    this.pourInCup();
-    this.addLemon();
+    this.boilWater()
+    this.brew()
+    this.pourInCup()
+    this.addCondiments()
   }
 
+  boilWater() {/*A*/}
+  brew() {/*A*/}
+  pourInCup() {/*A*/}
+  addCondiments() {/*A*/}
+}
+
+export class TeaPot extends HotDrinksPot {
   boilWater ()  {
-    this.algorithmSteps.boilWater = 'Boiling water';
+    this.algorithmSteps.boilWater = 'Boiling water'
   }
 
-  brewTea () {
-    this.algorithmSteps.brewTea = 'Steeping the tea';
+  brew () {
+    this.algorithmSteps.brew = 'Steeping the tea'
   }
 
   pourInCup () {
-    this.algorithmSteps.pourInCup = 'Pouring into cup';
+    this.algorithmSteps.pourInCup = 'Pouring into cup'
   }
 
-  addLemon () {
-    this.algorithmSteps.addLemon = 'Adding Lemon';
+  addCondiments () {
+    this.algorithmSteps.addCondiments = 'Adding Lemon'
   }
 }
 
-export class CoffeePot {
-  algorithmSteps = {};
-
-  constructor() {
-    this.prepareRecipe();
-  }
-
-  prepareRecipe () {
-    this.boilWater();
-    this.brewCoffee();
-    this.pourInCup();
-    this.addSugarAndMilk();
-  }
-
+export class CoffeePot extends HotDrinksPot {
   boilWater ()  {
-    this.algorithmSteps.boilWater = 'Boiling water';
+    this.algorithmSteps.boilWater = 'Boiling water'
   }
 
-  brewCoffee () {
-    this.algorithmSteps.brewCoffee = 'Dripping Coffee through filter';
+  brew () {
+    this.algorithmSteps.brew = 'Dripping Coffee through filter'
   }
 
   pourInCup () {
-    this.algorithmSteps.pourInCup = 'Pouring into cup';
+    this.algorithmSteps.pourInCup = 'Pouring into cup'
   }
 
-  addSugarAndMilk () {
-    this.algorithmSteps.addSugarAndMilk = 'Adding Sugar and Milk';
+  addCondiments () {
+    this.algorithmSteps.addCondiments = 'Adding Sugar and Milk'
   }
 }
diff --git a/src/patterns/22-visitor/example.js b/src/patterns/22-visitor/example.js
deleted file mode 100644
index 008f56b..0000000
--- a/src/patterns/22-visitor/example.js
+++ /dev/null
@@ -1,20 +0,0 @@
-const PdfMaker = {
-    makeFabricPdf(fabric) {
-
-    },
-    makeStoragePdf(storage) {
-        
-    },
-    makeCirclePdf(circle) {
-        
-    },
-}
-
-const Fabric = {
-}
-const Storage = {
-}
-const Circle = {
-}
-
-Visitor.makeFabricPdf(Fabric);
\ No newline at end of file
diff --git a/src/patterns/22-visitor/index.js b/src/patterns/22-visitor/index.js
index f8228d2..4b49684 100644
--- a/src/patterns/22-visitor/index.js
+++ b/src/patterns/22-visitor/index.js
@@ -1,17 +1,18 @@
 export class Visitor {
   constructor(compositeItem) {
-    this.compositeItem = compositeItem;
-    this.init();
+    this.compositeItem = compositeItem
+    this.init()
   }
 
   init () {
-    this.addGetSize();
-
-    // todo: add implementation
+    this.addGetSize()
+    this.compositeItem.children.forEach(child => child.accept(Visitor))
   }
 
   addGetSize () {
-    // todo: add implementation
+    this.compositeItem.getSize = () => {
+      return 1 + this.compositeItem.children.reduce((sum, child) => sum + child.getSize(), 0)
+    }
   }
 }
 
@@ -21,12 +22,12 @@ export class Comment {
     content = '',
     children = []
   } = {}) {
-    this.id = id;
-    this.content = content;
-    this.children = children;
+    this.id = id
+    this.content = content
+    this.children = children
   }
 
   accept (Visitor) {
-    new Visitor(this);
+    new Visitor(this)
   }
 }