Merge pull request #4093 from hozlucas28/Solution-23-TypeScript

#23 - TypeScript

Author: Roswell468

Roadmap/23 - SINGLETON/typescript/hozlucas28.ts

@@ -0,0 +1,214 @@
+/*
+    Singleton pattern...
+*/
+
+console.log('Singleton pattern...')
+
+interface ICounter {
+    getCount(): Counter['count']
+    decrement(): this
+    increment(): this
+}
+
+class Counter implements ICounter {
+    private static instance: Counter
+
+    private count: number
+
+    private constructor() {
+        this.count = 0
+    }
+
+    public static getInstance(): Counter {
+        if (!Counter.instance) {
+            Counter.instance = new Counter()
+        }
+
+        return Counter.instance
+    }
+
+    public getCount(): number {
+        return this.count
+    }
+
+    public decrement(): this {
+        this.count--
+        return this
+    }
+
+    public increment(): this {
+        this.count++
+        return this
+    }
+}
+
+const counter01: Counter = Counter.getInstance()
+const counter02: Counter = Counter.getInstance()
+
+console.log(
+    '\nAre `counter01` and `counter02` the same instance of `Counter` class?',
+    counter01 === counter02
+)
+
+console.log('\nMethod call of `counter01` instance...')
+
+counter01.increment().increment().increment()
+console.log('\ncounter01.increment().increment().increment()')
+
+console.log(
+    '\nCount attribute of `counter01` instance -->',
+    counter01.getCount()
+)
+
+console.log('\nMethod call of `counter02` instance...')
+
+counter02.decrement()
+console.log('\ncounter02.decrement()')
+
+console.log(
+    '\nCount attribute of `counter02` instance -->',
+    counter02.getCount()
+)
+
+console.log(
+    '\n# ---------------------------------------------------------------------------------- #\n'
+)
+
+/*
+    Additional challenge...
+*/
+
+console.log('Additional challenge...')
+
+interface IUserSession {
+    getEmail(): UserSession['email']
+    getId(): UserSession['id']
+    getName(): UserSession['name']
+    getUserName(): UserSession['userName']
+
+    setEmail(newEmail: UserSession['email']): this
+    setId(newId: UserSession['id']): this
+    setName(newName: UserSession['name']): this
+    setUserName(newUserName: UserSession['userName']): this
+
+    deleteData(): this
+}
+
+interface AUserSession {
+    email: string
+    id: string
+    name: string
+    userName: string
+}
+
+class UserSession implements IUserSession {
+    private static instance: UserSession
+
+    private email: AUserSession['email']
+    private id: AUserSession['email']
+    private name: AUserSession['email']
+    private userName: AUserSession['email']
+
+    private constructor({email, id, name, userName}: AUserSession) {
+        this.email = email
+        this.id = id
+        this.name = name
+        this.userName = userName
+    }
+
+    public static getInstance(
+        {
+            email = '',
+            id = '',
+            name = '',
+            userName = '',
+        }: Partial<AUserSession> = {
+            email: '',
+            id: '',
+            name: '',
+            userName: '',
+        }
+    ): UserSession {
+        if (!UserSession.instance) {
+            UserSession.instance = new UserSession({
+                email,
+                id,
+                name,
+                userName,
+            })
+        }
+
+        return UserSession.instance
+    }
+
+    public getEmail(): AUserSession['email'] {
+        return this.email
+    }
+
+    public getId(): AUserSession['id'] {
+        return this.id
+    }
+
+    public getName(): AUserSession['name'] {
+        return this.name
+    }
+
+    public getUserName(): AUserSession['userName'] {
+        return this.userName
+    }
+
+    public setEmail(newEmail: AUserSession['email']): this {
+        this.email = newEmail
+        return this
+    }
+
+    public setId(newId: AUserSession['id']): this {
+        this.id = newId
+        return this
+    }
+
+    public setName(newName: AUserSession['name']): this {
+        this.name = newName
+        return this
+    }
+
+    public setUserName(newUserName: AUserSession['userName']): this {
+        this.userName = newUserName
+        return this
+    }
+
+    public deleteData(): this {
+        this.email = ''
+        this.id = ''
+        this.name = ''
+        this.userName = ''
+
+        return this
+    }
+}
+
+const userSession: UserSession = UserSession.getInstance({
+    email: '[email protected]',
+    id: '155-AV25-12Z',
+    name: 'Juan',
+    userName: 'Juanceto01',
+})
+
+console.log(
+    '\nUser:',
+    userSession.getId(),
+    userSession.getName(),
+    userSession.getUserName(),
+    userSession.getEmail()
+)
+
+userSession.deleteData()
+console.log('\nUser data deleted!')
+
+console.log(
+    '\nUser:',
+    userSession.getId(),
+    userSession.getName(),
+    userSession.getUserName(),
+    userSession.getEmail()
+)