Code Refactoring

Author: faisalkarimi

Adapter.ts

@@ -17,7 +17,7 @@ interface Adapter {
  }
 
 // USAGE:
- const adapter = new InterfaceAdapter();
- adapter.request('param');
+const adapter = new InterfaceAdapter();
+adapter.request('param');
 // OUTPUT:
 // "Request made in old interface." 

Bridge.ts

@@ -43,11 +43,11 @@ class Commander {
  }
 
 // USAGE:
- const commanderA = new AirForceCommander(new Pilot());
- const commanderB = new SpecialForceCommander(new Soldier());
- 
- commanderA.order();
- commanderB.order();
+const commanderA = new AirForceCommander(new Pilot());
+const commanderB = new SpecialForceCommander(new Soldier());
+
+commanderA.order();
+commanderB.order();
 // OUTPUT:
 // "Air Force commander make order"
 // "Fly"

Composite.ts

@@ -54,24 +54,24 @@ interface ArmyObject {
  }
 
  // USAGE:
- const team = new Team('Seal Team 6');
- const specialSquad = new Team('Seal Team 6 - Special Squad');
- 
- const soldierJoe = new Soldier('Joe');
- const soldierJames = new Soldier('James');
- const soldierRoy = new Soldier('Roy');
- team.addSoldier(soldierJoe);
- team.addSoldier(soldierJames);
- team.addSoldier(soldierRoy);
- 
- const specialForceTommy = new Soldier('Tommy');
- 
- specialSquad.addSoldier(specialForceTommy);
- 
- team.operate();
- specialSquad.operate();
- 
- team.soldierGone(soldierJames);
+const team = new Team('Seal Team 6');
+const specialSquad = new Team('Seal Team 6 - Special Squad');
+
+const soldierJoe = new Soldier('Joe');
+const soldierJames = new Soldier('James');
+const soldierRoy = new Soldier('Roy');
+team.addSoldier(soldierJoe);
+team.addSoldier(soldierJames);
+team.addSoldier(soldierRoy);
+
+const specialForceTommy = new Soldier('Tommy');
+
+specialSquad.addSoldier(specialForceTommy);
+
+team.operate();
+specialSquad.operate();
+
+team.soldierGone(soldierJames);
  // OUTPUT:
  // "Soldier: Joe comes in Seal Team 6"
  // "Soldier: James comes in Seal Team 6" 

Decorator.ts

@@ -38,9 +38,9 @@ interface Coffee {
  }
 
 // USAGE:
- const general = new GeneralCoffee();
- const withBubble = new BubbleDecorator(general);
- const withMilk = new MilkDecorator(withBubble);
- console.log(`Total: ${withMilk.cost()}`);
+const general = new GeneralCoffee();
+const withBubble = new BubbleDecorator(general);
+const withMilk = new MilkDecorator(withBubble);
+console.log(`Total: ${withMilk.cost()}`);
 // OUTPUT:
 // "Total: 17"

Facade.ts

@@ -37,8 +37,8 @@ class EngineSystem {
  }
 
 // USAGE:
- const operation = new RocketTestingOperation();
- operation.operationStart();
+const operation = new RocketTestingOperation();
+operation.operationStart();
 // OUTPUT:
 // "Check system situations"
 // "Oxygen will be generated"

FactoryMethod.ts

@@ -38,13 +38,13 @@ interface Product {
  }
 
 // USAGE:
- const factory = new ProductFactory();
- const product1 = factory.createProduct('product-a');
- const product2 = factory.createProduct('product-b');
- const product3 = factory.createProduct('product-c');
- product1.doSomething();
- product2.doSomething();
- product3.doSomething();
+const factory = new ProductFactory();
+const product1 = factory.createProduct('product-a');
+const product2 = factory.createProduct('product-b');
+const product3 = factory.createProduct('product-c');
+product1.doSomething();
+product2.doSomething();
+product3.doSomething();
 // OUTPUT:
 // "Product A do this"
 // "Product A do this"

Flyweight.ts

@@ -48,13 +48,13 @@ interface Action {
  }
 
 // USAGE:
- const start = Math.floor(Date.now());
- for (let i = 0; i < 1000; i++) {
-  // new Soldier('normal-set', i); // create 1m real soldiers
-  SoldierAcademy.getSoldier('normal-set', i); // create 1 soldier
- }
- const end = Math.floor(Date.now());
- console.log(end - start);
+const start = Math.floor(Date.now());
+for (let i = 0; i < 1000; i++) {
+ // new Soldier('normal-set', i); // create 1m real soldiers
+ SoldierAcademy.getSoldier('normal-set', i); // create 1 soldier
+}
+const end = Math.floor(Date.now());
+console.log(end - start);
 // OUTPUT:
 // "new soldier 0" 
 // "shared soldier 1" 

Interpreter.ts

@@ -66,6 +66,7 @@ class AddExpression implements IntegerExpression {
  }
 }
 
+// USAGE:
 let context = new IntegerContext();
 
 let a = new IntegerVariableExpression("A");
@@ -79,4 +80,6 @@ context.assign(b, 1);
 context.assign(c, 3);
 
 const result = expression.evaluate(context);
-console.log(result); //6
+console.log(result); 
+// OUTPUT:
+//6

Iterator.ts

@@ -1,25 +1,58 @@
-type Novella = {
- name: string;
-};
+interface MyIterator {
+next(): any;
+hasNext(): boolean;
+}
+
+interface Aggregator {
+createIterator(): MyIterator;
+}
 
-type Novellas = {
- novellas: Novella[];
+class ConcreteIterator implements MyIterator {
+ private collection: any[] = [];
+ private position: number = 0;
 
- makeIterator(): NovellaIterator {
- return new NovellaIterator(novellas)
+ constructor(collection: any[]) {
+ this.collection = collection;
  }
-};
 
-class NovellaIterator {
- current = 0;
- novellas: Novella[];
+ public next(): any {
+ // Error handling is left out
+ var result = this.collection[this.position];
+ this.position += 1;
+ return result;
+ }
 
- constructor(novellas: Novella[]) {
- this.novellas = novellas;
+ public hasNext(): boolean {
+ return this.position < this.collection.length;
  }
+}
+
+class Numbers implements Aggregator {
+ private collection: number[] = [];
 
- next(): Novella {
- return this.novellas.length > this.current++ ? this.novellas[this.current] : null;
+ constructor(collection: number[]) {
+ this.collection = collection;
+ }
+ public createIterator(): MyIterator {
+ return new ConcreteIterator(this.collection);
  }
 }
+ 
+// USAGE:
+var nArray = [1, 7, 21, 657, 3, 2, 765, 13, 65],
+numbers: Numbers = new Numbers(nArray),
+it: MyIterator = numbers.createIterator();
 
+while (it.hasNext()) {
+console.log(it.next());
+}
+// OUTPUT:
+// 1
+// 7
+// 21
+// 657
+// 3
+// 2
+// 765
+// 13
+// 65

Observer.ts

@@ -1,79 +1,79 @@
 interface Observer {
- uniqueID: string;
- update(): void;
+ uniqueID: string;
+ update(): void;
+}
+
+class ConcreteObserver implements Observer {
+ public uniqueID: string
+ constructor(uniqueID: string) {
+ this.uniqueID = uniqueID;
  }
- 
- class ConcreteObserver implements Observer {
- public uniqueID: string
- constructor(uniqueID: string) {
- this.uniqueID = uniqueID;
- }
- 
- update(): void {
- console.log(`${this.uniqueID} updates something...`);
- }
+
+ update(): void {
+ console.log(`${this.uniqueID} updates something...`);
  }
- 
- function findObserver(obs: Observer[], uniqueID: string) {
- let index = 0;
- const existed = obs.some((observer, idx) => {
- index = idx;
- return observer.uniqueID === uniqueID;
- });
- return {
- existed,
- index
- };
+}
+
+function findObserver(obs: Observer[], uniqueID: string) {
+ let index = 0;
+ const existed = obs.some((observer, idx) => {
+ index = idx;
+ return observer.uniqueID === uniqueID;
+ });
+ return {
+ existed,
+ index
+ };
+}
+
+class Subject {
+ private _observers: Observer[];
+ constructor() {
+ this._observers = [];
  }
- 
- class Subject {
- private _observers: Observer[];
- constructor() {
- this._observers = [];
+
+ registerObserver(ob: Observer) {
+ const id: string = ob.uniqueID;
+ if (findObserver(this._observers, id).existed) {
+ return console.log(`Observer ${id} is already in list`);
  }
- 
- registerObserver(ob: Observer) {
- const id: string = ob.uniqueID;
- if (findObserver(this._observers, id).existed) {
- return console.log(`Observer ${id} is already in list`);
- }
- this._observers.push(ob);
- console.log(`Observer ${ob.uniqueID} is pushed into list`);
- console.log(this._observers);
- }
- 
- removeObserver(uniqueID: string) {
- const { existed, index } = findObserver(this._observers, uniqueID);
- if (existed) {
- this._observers.splice(index, 1);
- console.log(`Observer ${uniqueID} is removed from list`);
- } else {
- console.log('Observer not existed');
- }
- }
- 
- notifyObservers() {
- console.log('Subject notify all observers >>');
- this._observers.map((observer) => {
- observer.update();
- });
+ this._observers.push(ob);
+ console.log(`Observer ${ob.uniqueID} is pushed into list`);
+ console.log(this._observers);
+ }
+
+ removeObserver(uniqueID: string) {
+ const { existed, index } = findObserver(this._observers, uniqueID);
+ if (existed) {
+ this._observers.splice(index, 1);
+ console.log(`Observer ${uniqueID} is removed from list`);
+ } else {
+ console.log('Observer not existed');
  }
  }
+
+ notifyObservers() {
+ console.log('Subject notify all observers >>');
+ this._observers.map((observer) => {
+ observer.update();
+ });
+ }
+}
 
 // USAGE:
- const subject = new Subject();
- 
- const obA = new ConcreteObserver('A');
- const obB = new ConcreteObserver('B');
- const obC = new ConcreteObserver('C');
- 
- subject.registerObserver(obA);
- subject.registerObserver(obA); // already existed
- 
- subject.registerObserver(obB);
- subject.registerObserver(obC);
- 
- subject.notifyObservers();
+const subject = new Subject();
+
+const obA = new ConcreteObserver('A');
+const obB = new ConcreteObserver('B');
+const obC = new ConcreteObserver('C');
+
+subject.registerObserver(obA);
+subject.registerObserver(obA); // already existed
+
+subject.registerObserver(obB);
+subject.registerObserver(obC);
+
+subject.notifyObservers();
 // OUTPUT:
 // "Observer A is pushed into list"
 // "Observer A is already in list"