试图让淘汰赛js检查数据是否每10秒来一次

Question

我正在尝试调用ajax请求来检查数据库的函数，每隔10秒查看一下我想要的信息是否已经到达，如果所需信息未到达60秒，我只想退出该功能。 我现在遇到的问题是，我的功能每10秒钟不会调用self.startInstantorCheck，然后在60秒后退出到最后。 下面是函数

所有的

self.startInstatorCheck = function(){ 
       self.instatorStarts(true); 
       var MAX_WAIT_TIME_MS = 1 * 60 * 1000; 
       var POST_INTERVAL_MS = 10 * 1000; 
       var timeoutTime = null; 
       $.ajax({ 
         type: 'POST', 
         url: BASEURL + 'index.php/moneyexchange/check_instantor_field/' + auth, 
         contentType: 'application/json; charset=utf-8' 
        }) 
       .done(function(userinfo) { 
        if (timeoutTime == null) { 
         // Start of the timeout cycle: 
         timeoutTime = Date.now() + MAX_WAIT_TIME_MS; 
        } 
        if (userinfo.instantor_request > 12) { 
         self.allInstantorCheckMessages('Instantor data gathered'); 
        } else { 
         if (Date.now() < MAX_WAIT_TIME_MS) { 
         setTimeout(self.startInstatorCheck(), POST_INTERVAL_MS); 
         } else { 
          self.allInstantorCheckMessages('Please go through instantor to '); 
          self.instatorStarts(true); 
          self.magicInstantorbtn2(true); 
         } 
        } 
       }) 
       .fail(function(jqXHR, textStatus, errorThrown) { 
        self.errorMessage(errorThrown); 
       }) 
       .always(function(data){    
       }); 
     } 
I am using knockout js, so would be great if the answers or help are related to knockout js. 

Answer 1

首先，这里是你的简化，以减少嵌套，并通过命名提供清晰的代码。

  self.startInstatorCheck = function(){ 
       self.instatorStarts(true); 
       var MAX_WAIT_TIME_MS = 1 * 60 * 1000; 
       var POST_INTERVAL_MS = 10 * 1000; 
       var timeoutTime = null; 
       $.ajax({ 
         type: 'POST', 
         url: BASEURL + 'index.php/moneyexchange/check_instantor_field/' + auth, 
         contentType: 'application/json; charset=utf-8' 
        }) 
       .done(function(userinfo) { 
        // please use === not == 
        // == doesn't always do what you want it to do, NEVER use it 
        timeoutTime = timeoutTime === null ? 
         Date.now() + MAX_WAIT_TIME_MS : 
         timeoutTime; 

        var pleaseNameMe = userinfo.instantor_request > 12 
        if (pleaseNameMe) { 
         return self.allInstantorCheckMessages('Instantor data gathered'); 
        } 

        var expired = Date.now() < MAX_WAIT_TIME_MS 
        if (!expired) { 
         return setTimeout(self.startInstatorCheck(), POST_INTERVAL_MS); 
        } 

        self.allInstantorCheckMessages('Please go through instantor to '); 
        self.instatorStarts(true); 
        self.magicInstantorbtn2(true); 

       }) 
       .fail(function(jqXHR, textStatus, errorThrown) { 
        self.errorMessage(errorThrown); 
       }) 
       .always(function(data){    
       }); 
     } 

其次，你的问题已经解决了，knockoutjs与否。 Here is a wonderful article解释如何使用超时在JavaScript中进行轮询。它建议使用承诺。我非常同意。 （他们可以并且应该与knockout js一起使用。）直接来自博客的一个人为的例子：

// The polling function 
function poll(fn, timeout, interval) { 
    var dfd = new Deferred(); 
    var endTime = Number(new Date()) + (timeout || 2000); 
    interval = interval || 100; 

    (function p() { 
      // If the condition is met, we're done! 
      if(fn()) { 
       dfd.resolve(); 
      } 
      // If the condition isn't met but the timeout hasn't elapsed, go again 
      else if (Number(new Date()) < endTime) { 
       setTimeout(p, interval); 
      } 
      // Didn't match and too much time, reject! 
      else { 
       dfd.reject(new Error('timed out for ' + fn + ': ' + arguments)); 
      } 
    })(); 

    return dfd.promise; 
} 

// Usage: ensure element is visible 
poll(function() { 
    return document.getElementById('lightbox').offsetWidth > 0; 
}, 2000, 150); 

Answer 2

你的代码中几乎没有错误。

比较这与你看到的变化

self.startInstatorCheck = function() { 
    self.instatorStarts(true); 
    var t = new Date(); 
    var timeoutTime = t.setSeconds(t.getSeconds() + 60) 
    var interval = 10 * 1000; 

    function instatorCheck() { 
     $.ajax({ 
       type: 'POST', 
       url: BASEURL + 'index.php/moneyexchange/check_instantor_field/' + auth, 
       contentType: 'application/json; charset=utf-8' 
      }) 
      .done(function(userinfo) { 
       if (userinfo.instantor_request > 12) { 
        self.allInstantorCheckMessages('Instantor data gathered'); 
       } else { 
        if (new Date() < timeoutTime) { 
         setTimeout(instatorCheck, interval); 
        } else { 
         self.allInstantorCheckMessages('Please go through instantor to '); 
         self.instatorStarts(true); 
         self.magicInstantorbtn2(true); 
        } 
       } 
      }) 
      .fail(function(jqXHR, textStatus, errorThrown) { 
       self.errorMessage(errorThrown); 
      }) 
      .always(function(data) {}); 
    } 
    instatorCheck(); 
}