Private property in js class

class Person {
    constructor(name) {
        this.name = name  // Public attributes}}Copy the code
  • classThe keyword is just syntax sugar, no can be implemented
class Login {
    constructor(username, password) {
        this.username = username
        this.password = password
    }
}
const xguo = new Login('guo'.'88888888')
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  • How do I make the password property private? That is, out of class is not accessible

  • Closure?

let obj = (function() {
    // Closed Spaces are private
    return () = >{}}) ()Copy the code

  • Closure, where local variables can be read only by children inside a function

  • How do I set up a key stored in an object that is not externally accessible? Symbol!

class Login {
    constructor(username, password) {
        this.username = username
        const PASSWORD = Symbol(a)this[PASSWORD] = password
    }
    checkPassword(pwd) {
        return this[PASSWORD] == pwd
    }
}

var userA = new Login('aa'.'123456')
console.log(userA.checkPassword(123456));
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  • Symbol sets a unique key to avoid public access

  • How do you access the symbol as key property in the object?

const gender = Symbol('gender')
const obj = {
    name: 'guo'.age: 17,
    [gender]: 'man'
}

console.log(obj[gender]);  // man
console.log(Object.getOwnPropertySymbols(obj));  // [ Symbol(gender) ]
console.log(Reflect.ownKeys(obj));  // [ 'name', 'age', Symbol(gender) ]
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  • You can useObject.getOwnPropertySymbols()andReflect.ownKeys()Get to the