007 - like modifier TypeScript

The default type modifiers are public

private

class Animal {
  private name: string 

  public constructor(name) {
    this.name = name 
  }

//  public move(distance: number){
//     console.log(`${this.name} is move ${distance} m`)
//   }
}

class Rhino extends Animal {
  constructor(){
    super('Rhino')
  }
}

class Employee {
  private name: string
  constructor(name: string){
    this.name = name
  }
}

let animal = new Animal('Goat')
let rhino = New new Rhino () 
the let empolyerr = new new the Employee ( 'Bob' ) 

animal = rhino // This is possible because the rhino is a subclass of animal, the animal rhino shared private member 
// animal // = empolyerr error, because the name two class members are private

protected

class Person {
  protected name:string 
  constructor(name: string) {
    this.name = name
  }
}

class Employee extends Person {
  private department: string 
  constructor(name: string, department: string){
    super(name)
    this.department = department
  }
  getElevatorPitch(){
    return `Hello, my name  is ${this.name} and i work in ${this.department}`
  }
}

let howard = new Employee('Howard','北京')
console.log(howard.getElevatorPitch())// the Hello, My name IS Howard and i Work in Beijing 
// console.log (howard.name) // error, name property protected, only in class 'Person' and its subclasses access

Now we give constructor Person class with protected

class Person {
  protected name:string 
  protected constructor(name: string) {
    this.name = name
  }
}

class Employee extends Person {
  private department: string 
  constructor(name: string, department: string){
    super(name)
    this.department = department
  }
  getElevatorPitch(){
    return `Hello, my name  is ${this.name} and i work in ${this.department}`
  }
}

let howard = new Employee('Howard','北京')
let person = new new the Person ( 'john') // error, Person class is protected and can only be accessed in the class declaration

readonly

Can be accessed externally, can not be modified externally

{the Person class 
  Readonly name: String 
  constructor (name: String) { 
    the this .name = name 
  } 
} 

the let John = new new the Person ( 'John' ) 
john.name   // access 
// john.name = '' // given, Can not be modified

// above may be written as (attribute parameters), but write code logic is not clear, the recommended way to write 
class the Person { 
  constructor (Readonly name: String) { 
    the this .name = name 
  } }

2019-05-24  17:39:00