javascript - Promise.all() 每个 promise 响应

Question

我需要在循环中调用 asyncc 操作:

for (var i = 0; i < message.destinatarios.length; i++) {
  messageList.push(this.sms.send(destinatario.numero_celular, string));
 // this will take a litle time to be executed
}

// Here I need something to be fired each time one of the promises in messageList is resolved

Promise.all(messageList)
  .then(res => {
     //that is executed when all the promises have been resolved 
  })
  .catch(err => {
     // that is executed when some of then fail
  });

然后对于每个响应，我需要增加一个这样的计数器

console.log("processing " + counter++ + " of " + messageList.length);

由于我需要等待所有 promise 都得到履行，直到进入下一步，我该如何正确地做到这一点？

Answer 1

您可以为每个 Promise 分配一个 resolveCallback。然后，使用 Promise.all() 等待所有 Promise 完成需要等待所有 Promise 完成的工作。

let counter = 0;
for (var i = 0; i < message.destinatarios.length; i++) {
  const prom = this.sms.send(destinatario.numero_celular, string);
  messageList.push(prom);
  prom.then(() => {
    //your logic for whatever you want to do for every time a promise is resolved
    console.log("processing " + ++counter + " of " + messageList.length); 
  })
}
Promise.all(messageList)