JS Promise waitFor refresh令牌

如果我理解这一点,我们需要做两件事:

• 在进行刷新令牌时,不要多次调用我们的刷新令牌

如果您将可观察的模式和状态结合起来以保持进行中的状态,则可以如下所示

// MyObservable.js:
var util = require('util');
var EventEmitter = require('events').EventEmitter;

let inProgress = false;

function MyObservable() {
  EventEmitter.call(this);
}
// This is the function responsible for getting a refresh token
MyObservable.prototype.getToken = function(token) {
  console.log('Inside getToken');
  if (!inProgress) {
    console.log('calling fetchToken');
    resultPromise = this.fetchToken();
    inProgress = true;
    resultPromise.then((result) => {
      console.log('Resolved fetch token');
      inProgress = false;
      this.emit('done', 'token refreshed');
    });
  }

}
// This is a mock function to simulate the promise based API.
MyObservable.prototype.fetchToken = function(token) {
  console.log('Inside fetchToken');
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      console.log('resolving');
      resolve("Completed");
    }, 2000);
  });
}

util.inherits(MyObservable, EventEmitter);
module.exports = MyObservable;

现在我们可以实现这一点,并观察调用是否完成

const MyObservable = require('./MyObservable');

const observable = new MyObservable();


const A = () => {
  console.log('Inside A');
  observable.on('done', (message) => {
    console.log('Completed A');
  });
  observable.getToken('test');
}

for (let i = 0; i < 5; i++) {
  setTimeout(A, 1000);
}

fetchToeken 即使我们的方法 A

希望这有帮助!