Question

我是Node.js和异步编程的新手，我有一个问题。我需要在递归循环中连续工作服务器，这些步骤将一致地实现，并且每个阶段应该包括在websotskets上的异步接收数据（这已经被理解），或者在计时器到期时进入下一阶段。我知道这不是一项微不足道的任务，而是如何实现它，图书馆可以提供哪些帮助？我试图了解Step.js和Node.js事件，这是我需要的吗？

如果我同步写下所有这些：

//CODE FOR STACKOVERFLOW
var previous_round = 'qwerty';// this is string, selected in previous cycle
var round_users = users;// 'users' is array of soceket.id all connected users and here a put them into new array 'round_users' with sockets for current cycle
io.sockets.emit('users_round', { number: round_users.length }); // send to users information about number of users in new round
for (var i = 0; i < round_users.length; i++) {
      io.sockets.socket(round_users[i]).emit('round', { text: previous_round });//for each socket in 'round_users' emit event to enter chat message
}                                                                               // and send selected in previous round message
var messages = []; // array of users messages
//now we must listen users events and start timer for next stage
  //listen users events
  for (var i = 0; i < round_users.length; i++) {
        io.sockets.socket(round_users[i]).on('message', function (data) {
          messages[messages.length] = data.text;//write text from users to array
          if (messages.length == round_users.length) { /* GO TO NEXT STAGE */ } // it's after previous operation in this function
        });
  } 
  //or set timeout
  setTimeout(/* GO TO NEXT STAGE */,15000);
for (var i = 0; i < round_users.length; i++) {
      io.sockets.socket(round_users[i]).emit('voting', { messages_array: messages });//for each socket in 'round_users' emit event to vote perfect chat message
}                                                                                    // and send messages, which they send to server
//i'm not quite sure about this decision of vote counting :-)
var votes = []; //array with users votes
for (var i = 0; i < messages.length; i++) {
      votes[i] = 0;
}   
//now we must listen users events and start timer
  //listen users events
  for (var i = 0; i < round_users.length; i++) {
        io.sockets.socket(round_users[i]).on('vote', function (data) {
          votes[data.number]++;//increment selected message
          if (votes.length == messages.length) { /* GO TO NEXT STAGE */ } // it's after previous operation in this function
        });
  } 
  //or set timeout
  setTimeout(/* GO TO NEXT STAGE */,10000);
var max_id = 0; //now select max number from 'votes' array
for (var i = 0; i < votes.length; i++) {
      if (votes[i]>votes[max_id]) {max_id = i;} //yet without the same values
}   
var previous_round = messages[max_id]; //set up string value of selected message
//restart cycle

语法高亮显示

this code on pastebin

Answer 1

最基本意义上的递归只是一个一次又一次调用自身的函数，但在这个实例中，您可能希望利用process.nextTick()允许在此递归过程中发生其他事件。

以下是您可以采用的一种方式的简单示例：

function someFunction(args, callback) {
  // Check requirements
  if (typeof callback !== 'function') return console.log('Callback required');
  if (typeof args === 'undefined') return callback('Arguments required');

  // Set defaults
  var err = false;
  var result = false;

  // Do other stuff
  anotherFunctionWithAcallback(args, function(err, result) {
    if (err) return callback(err);
    // This way, the nextTick only occurs after processing completes
    return callback(err, result); 
  }
}

(function loop(stage) {
  // When the stage argument is not provided, default to stage 1
  stage = (typeof stage === 'undefined') ? 1 : stage;
  switch(stage) {
    case 1:
      /* stage 1 */
      someFunction(args, function(err, result){
        process.nextTick(loop(2));
      });
    break;
    case 2:
      /* stage 2 */
      someFunction(args, function(err, result){
        process.nextTick(loop(3));
      });
    break;
    case 3:
      /* stage 3 */
      someFunction(args, function(err, result){
        // No stage argument, restart at stage 1 by default
        process.nextTick(loop());
      });
    break;
  }
})(); // Execute this function immediately

Node.js中的分阶段执行递归循环

1 个答案: