如何阻止在创建另一个对象后覆盖原型中的函数的参数

Question

为了避免相同函数的复制，我听说函数必须在 prototype 中定义。我听说 OOP 继承很糟糕，这就是为什么我在 Javascript 深入研究时尝试使用工厂函数。但是我在下面的代码中遇到了问题。我在 prototype 中定义了所有函数并创建了两个对象，emp 和 emp2。但是在定义了emp2之后，emp的参数被覆盖了。那么工厂函数和原型有什么好处呢？

const eater = (state) => ({
  eat(){
    console.log(state.name, 'is eating')
  }
})



function createEmployee(name, age){
  let Employee = Object.create
    (createEmployee.prototype)
  Employee.name = name 
  Employee.age = age 
  
  Object.assign(
    createEmployee.prototype, 
    eater(Employee)
  )
  
  createEmployee.prototype.work = function(){
    console.log(Employee.name, 'is working')
  } 
 
  
  return Employee
}

let emp = createEmployee('Muzaffer', 24)
emp.work()
emp.eat()
let emp2 = createEmployee('Cuma', 22)
emp.work()
emp.eat()
//Output 
//Muzaffer is working
//Muzaffer is eating
//Cuma is working
//Cuma is eating

Answer 1

使用this关键字时有效

const eater = () => ({
  eat(){
    console.log(this.name, 'is eating')
  }
})

Object.assign(
  createEmployee.prototype, 
  eater()
)
 

function createEmployee(name, age){
    
  let Employee = Object.create(createEmployee.prototype)
   
  this.name = name 
  this.age = age 
   
  return Object.assign(Employee, this)
}

createEmployee.prototype.work = function(){
  console.log(this.name, 'is working')
} 

let emp = createEmployee('Muzaffer', 24)
console.log(emp.name)
emp.work()
emp.eat()
let emp2 = createEmployee('Cuma', 22)
console.log('after creating emp2')
emp.work()
emp.eat()
console.log(emp.name)


/*
  
  //Output
 
Muzaffer
Muzaffer is working
Muzaffer is eating
after creating emp2
Muzaffer is working
Muzaffer is eating
Muzaffer
  
  
  
*/

Answer 2

使用 this 关键字而不使用 new 关键字时不起作用。

"use strict";
const eater = () => ({
  eat(){
    console.log(this.name, 'is eating')
  }
})

Object.assign(
  createEmployee.prototype, 
  eater()
)
 

function createEmployee(name, age){
    
  let Employee = Object.create(createEmployee.prototype)
   
  this.name = name 
  this.age = age 
   
  return Object.assign(Employee, this)
}

createEmployee.prototype.work = function(){
  console.log(this.name, 'is working')
} 

let emp = createEmployee('Muzaffer', 24)
console.log(emp.name)
emp.work()
emp.eat()
let emp2 = createEmployee('Cuma', 22)
console.log('after creating emp2')
emp.work()
emp.eat()
console.log(emp.name)

有new个关键字

const eater = () => ({
  eat(){
    console.log(this.name, 'is eating')
  }
})

Object.assign(
  createEmployee.prototype, 
  eater()
)
 

function createEmployee(name, age){
  
  this.name = name 
  this.age = age 
  
}
createEmployee.prototype.work = function(){
  console.log(this.name, 'is working')
} 

let emp = new createEmployee('Muzaffer', 24)
console.log(emp.name)
emp.work()
emp.eat()
let emp2 = new createEmployee('Cuma', 22)
console.log('after creating emp2')
emp.work()
emp.eat()
console.log(emp.name)

根据这些结果：new 关键字只是使 this 对象的原型引用 createEmployee.prototype，就像之前的 Object.create 调用一样。和 return this 对象。使用 new 关键字调用函数或仅调用常规函数时 this 对象自动创建。

但是我们不需要在 createEmployee 工厂函数中使用 this 关键字。我们只需要在我们的对象函数中使用 this 关键字，例如 work 和 eat.

const eater = () => ({
  eat(){
    console.log(this.name, 'is eating')
  }
})

Object.assign(
  createEmployee.prototype, 
  eater()
)
 

function createEmployee(name, age){
    
  let Employee = Object.create(createEmployee.prototype)
   
  Employee.name = name 
  Employee.age = age 
   
  return Employee 
}

createEmployee.prototype.work = function(){
  console.log(this.name, 'is working')
} 

let emp = createEmployee('Muzaffer', 24)
console.log(emp.name)
emp.work()
emp.eat()
let emp2 = createEmployee('Cuma', 22)
console.log('after creating emp2')
emp.work()
emp.eat()
console.log(emp.name)

如何阻止在创建另一个对象后覆盖原型中的函数的参数

How to block parameters of function which is in prototype overrided after created another object

javascript

prototype