javascript - 如何处理嵌套 Promise 的结果

Question

我在重构一些代码以使用 Promises 时遇到问题，这是为了避免嵌套回调，我尝试重构的代码如下所示:

bot.api.users.list({}, function(err, teamData) {
if(err) {
  bot.botkit.log("Couldn't fetch team data from API", err);
  return;
}

var members = teamData.members;
var msgSender = _.find(members, function(member) { return member.id == message.user });

parsedUserIds(userIdsGroup).forEach(function(id) {
  var msgReceiver = _.find(members, function(member) { return member.id == id });

  bot.startPrivateConversation({ user: id }, function(err, conversation) {
    if(err) {
      bot.botkit.log("Couldn't initiate private conversation", err);
      return;
    }

    var message = format("Hey {to}, {from} just requested a Pull Request Review, here's the link: {githubLink}, please go and check it out!", 
                         { to: msgReceiver.name,
                           from: msgSender.name,
                           githubLink: githubRepoUrl });

      conversation.say(message);
  });
});

我使用带有 slack api 的 botkit 和用于 Promises 的 bluebird。

代码中我遇到最多麻烦的部分是循环遍历每个 id 并开始与用户的私有(private)对话；我一直在尝试的看起来像这样:

  var usersList = Promise.promisify(bot.api.users.list);
  var privateConversation = Promise.promisify(bot.startPrivateConversation);

  usersList({}).then(function(data) {
    var members = data.members;
    var msgSender = findMember(members, message.user);

    return Promise.all(parsedUserIds(userIdsGroup).map(function(id) {
      var msgReceiver = findMember(members, id);

      return privateConversation({ user: id }).then(function(conversation) {
        var message = format("Hey {to}, {from} just requested a Pull Request Review, here's the link: {githubLink}, please go and check it out!", 
                             { to: msgReceiver.name,
                               from: msgSender.name,
                               githubLink: githubRepoUrl });
        conversation.say(message);
      });
    }));
  }).catch(function(err){
    bot.botkit.log(err);
  });

据我了解，Promise.all 允许我从一系列 promise 中获取结果...但是，我从此代码中收到错误: TypeError: this.task.bot.reply is不是一个对我没有任何帮助的函数。

我如何使用 Promise 来完成我想要做的事情？

Answer 1

Promise.all allows me to get a result from an array of promises

Promise.all 返回一个 promise ，一旦您传入的所有 promise 都得到履行，该 promise 就会得到履行。所以你需要做的是调用then就可以了

Promise.all(parsedUserIds(userIdsGroup).map(function(id) {/*return promise here*/}))
.then(function(results) { console.log(results); })