Node.js中分阶段执行recursion循环
我是一般的Node.js和asynchronous编程的新手，我有一个问题。 我需要在recursion循环中连续工作的服务器，这些步骤将被一致地执行，并且每个阶段应该包括通过websotskets（这已经被理解）的asynchronous接收数据，或者在计时器到期时进入下一阶段。 我意识到，这不是一个小任务，而是如何实现它，图书馆可以提供什么帮助？ 我试图理解Step.js和Node.js事件，这是我需要什么？
如果我写了所有这一切同步：
//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 这个代码在语法高亮的pastebin上
从最基本的意义上讲，recursion只是一个一次又一次地调用自己的函数，但在这个例子中，你可能想利用process.nextTick（）来允许其他事件在recursion过程中发生。
这里有一个简单的例子，你可以去看看它：
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