从函数返回的结果（javascript中，的NodeJS） [英] return results from a function (javascript, nodejs)

问题描述

谁能帮我这个code？我需要返回一个值形成routeToRoom功能：

  VAR SYS =要求（'SYS'）;  功能routeToRoom（用户ID，PASSW）{
      变种roomId = 0;
      VAR nStore =要求（'nstore / lib目录/ nstore'）扩展（需要（'nstore / lib中/ nstore /查询）（））;
      VAR用户= nStore.new（数据/ users.db'，函数（）{          users.find（{
              用户：用户ID
              传：PASSW
          }，（功能（错了，结果）{
              如果（ERR）{
                  roomId = -1;
              }其他{
                  roomId = results.creationix.room;
              }
          }））;
      }）;
      返回roomId;
  }
  sys.puts（routeToRoom（亚历克斯，123））;
 

不过，我总是得到：0

我猜返回roomId; 之前 roomId = results.creationix.room 执行。可能有人能帮我解决这个code？

解决方案

 函数routeToRoom（用户ID，PASSW，CB）{
    变种roomId = 0;
    VAR nStore =要求（'nstore / lib目录/ nstore'）扩展（需要（'nstore / lib中/ nstore /查询）（））;
    VAR用户= nStore.new（数据/ users.db'，函数（）{
        users.find（{
            用户：用户ID
            传：PASSW
        }，功能（错了，结果）{
            如果（ERR）{
                roomId = -1;
            }其他{
                roomId = results.creationix.room;
            }
            CB（roomId）;
        }）;
    }）;
}
routeToRoom（亚历克斯，123，功能（ID）{
    的console.log（ID）;
}）;
 

您需要使用回调。这就是IO如何异步工作。顺便说一句 sys.puts 是德precated

Could anyone help me with this code? I need to return a value form a routeToRoom function:

  var sys = require('sys');

  function routeToRoom(userId, passw) {
      var roomId = 0;
      var nStore = require('nstore/lib/nstore').extend(require('nstore/lib/nstore/query')());
      var users = nStore.new('data/users.db', function () {

          users.find({
              user: userId,
              pass: passw
          }, (function (err, results) {
              if (err) {
                  roomId = -1;
              } else {
                  roomId = results.creationix.room;
              }
          }));
      });
      return roomId;
  }
  sys.puts(routeToRoom("alex", "123"));

But I get always: 0

I guess return roomId; is executed before roomId=results.creationix.room. Could someone help me with this code?

解决方案

function routeToRoom(userId, passw, cb) {
    var roomId = 0;
    var nStore = require('nstore/lib/nstore').extend(require('nstore/lib/nstore/query')());
    var users = nStore.new('data/users.db', function() {
        users.find({
            user: userId,
            pass: passw
        }, function(err, results) {
            if (err) {
                roomId = -1;
            } else {
                roomId = results.creationix.room;
            }
            cb(roomId);
        });
    });
}
routeToRoom("alex", "123", function(id) {
    console.log(id);    
});

You need to use callbacks. That's how asynchronous IO works. Btw sys.puts is deprecated

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