Paperback 
Factory Design Pattern
Video Lecture
| Section | Video Links |
|---|---|
| Factory Pattern |   |
| Factory Use Case | |
Overview
...Refer to Book or Videos for extra content.
Terminology
...Refer to Book or Videos for extra content.
Factory UML Diagram
Source Code
...Refer to Book or Videos for extra content.
./src/factory/factory-concept.ts
// The Factory Concept
interface IProduct {
name: string
}
class ConcreteProduct implements IProduct {
name = ''
}
class ConcreteProductA extends ConcreteProduct {
constructor() {
super()
this.name = 'ConcreteProductA'
}
}
class ConcreteProductB extends ConcreteProduct {
constructor() {
super()
this.name = 'ConcreteProductB'
}
}
class ConcreteProductC extends ConcreteProduct {
constructor() {
super()
this.name = 'ConcreteProductC'
}
}
class Creator {
static createObject(someProperty: string): IProduct {
if (someProperty === 'a') {
return new ConcreteProductA()
} else if (someProperty === 'b') {
return new ConcreteProductB()
} else {
return new ConcreteProductC()
}
}
}
// The Client
const PRODUCT = Creator.createObject('b')
console.log(PRODUCT.name)
Output
node ./dist/factory/factory-concept.js
ConcreteProductB
Factory Use Case
...Refer to Book or Videos for extra content.
Factory Example UML Diagram
Source Code
./src/factory/client.ts
// Factory Use Case Example Code
import ChairFactory from './chair-factory'
const CHAIR = ChairFactory.getChair('SmallChair')
console.log(CHAIR.getDimensions())
./src/factory/dimension.ts
export type dimension = {
height: number
width: number
depth: number
}
./src/factory/chair.ts
import { dimension } from './dimension'
// A Chair Interface
interface IChair {
height: number
width: number
depth: number
getDimensions(): dimension
}
// The Chair Base Class
export default class Chair implements IChair {
height = 0
width = 0
depth = 0
getDimensions(): dimension {
return {
width: this.width,
depth: this.depth,
height: this.height,
}
}
}
./src/factory/chair-factory.ts
import SmallChair from './small-chair'
import MediumChair from './medium-chair'
import BigChair from './big-chair'
import IChair from './chair'
export default class ChairFactory {
static getChair(chair: string): IChair {
if (chair == 'BigChair') {
return new BigChair()
} else if (chair == 'MediumChair') {
return new MediumChair()
} else {
return new SmallChair()
}
}
}
./src/factory/small-chair.ts
import Chair from './chair'
export default class SmallChair extends Chair {
constructor() {
super()
this.height = 40
this.width = 40
this.depth = 40
}
}
./src/factory/medium-chair.ts
import Chair from './chair'
export default class MediumChair extends Chair {
constructor() {
super()
this.height = 60
this.width = 60
this.depth = 60
}
}
./src/factory/big-chair.ts
import Chair from './chair'
export default class BigChair extends Chair {
constructor() {
super()
this.height = 80
this.width = 80
this.depth = 80
}
}
Output
node ./dist/factory/client.js
{'width': 40, 'depth': 40, 'height': 40}
Summary
...Refer to Book or Videos for extra content.