将属性引用从一类传递到另一类

Question

Say I've got 2 classes Auth and Client . If I have a property Auth.token I would like to be able to pass that property to Client.token as a reference so that when I change Auth.token it also changes the value of Client.token .

Here's an simplified example that currently doesn't work..

class Auth {
  constructor() {
    this._token = '123';
  }
  get token() {
    return this._token;
  }
  updateToken(newToken) {
    this._token = newToken;
  }
}

class Client {
  constructor(token) {
    this._token = token;
  }
  fetch() {
    console.log(this._token);
  }
}

const auth = new Auth();
const client = new Client(auth.token);
client.fetch();
auth.updateToken('abc');
client.fetch();

Answer 1

You could pass your Auth instance to your Client instance and access token through Auth . This would ensure that updates to the Auth._token would effect the Client :

 class Auth { constructor() { this._token = '123'; } get token() { return this._token; } updateToken(newToken) { this._token = newToken; } } class Client { constructor(auth) { this._auth = auth; } fetch() { console.log(this._auth.token); } } const auth = new Auth(); const client = new Client(auth); client.fetch(); auth.updateToken('abc'); client.fetch(); 

Answer 2

Making a global variable would be one way of achieving this. You can then simply update the token via the Auth .

 let token = '' class Auth { constructor() { token = '123'; } get token() { return token; } updateToken(newToken) { token = newToken; } } class Client { fetch() { console.log(token); } } const auth = new Auth(); const client = new Client(); client.fetch(); auth.updateToken('abc'); client.fetch();