jQuery：等待函数完成继续处理？ [英] jQuery: wait for function to complete to continue processing?

问题描述

嘿所有人。我看起来似乎是一个微不足道的问题。我有以下JavaScript：

  $（function（）{
 var r = GetResults（）; 
 
 for（var i = 0; i< r.length; i ++）{
 //用r 
做东西} 
}）; 
 
函数GetResults（）{
 $ .getJSON（/ controller / method /，null，function（data）{
 return data; 
}）; 
} 
  

由于我正在异步调用方法，脚本继续执行，当遇到for循环时， r 显然还没有值。我的问题是：当我有一个正在进行异步操作的方法，并且我依赖于它在主块中返回的数据时，如何在数据返回之前暂停执行？类似于：

  var r = GetResults（param，function（）{
 
}）; 
  

其中函数是回调函数。我无法将for循环处理移动到JSON请求的回调函数中，因为我在整个页面中多次重用GetResults的功能，除非我想复制代码。有什么想法吗？

解决方案

将你的用r做块块移到$ .getJSON回调中。在你交付之前你不能用r做东西，你必须使用r的第一个机会就是回调...那么就这样做。

  $（function（）{
 var r = GetResults（）; 
}）; 
 
函数GetResults（）{
 $ .getJSON（/ controller / method /，null，function（data）{
 for（var i = 0; i< data.length; i ++）{
 //用数据做
} 
返回数据; 
}）; 
} 
  

Hey all. I have, what appears to be, a trivial problem. I have the following JavaScript:

$(function() {
    var r = GetResults();

    for(var i = 0; i < r.length; i++) {
        // Do stuff with r
    }
});

function GetResults() {
   $.getJSON("/controller/method/", null, function(data) {
       return data;
   });
}

Due to the fact that I'm calling a method asynchronously, the script continues executing and when it encounters the for loop, r obviously isn't going to have a value yet. My question is: when I have a method that is doing an asynchronous operation, and I'm dependent on the data it returns back in the main block, how do I halt execution until the data is returned? Something like:

var r = GetResults(param, function() {

});

where the function is a callback function. I cannot move the for loop processing into the callback function of the JSON request because I am reusing the functionality of GetResults several time throughout the page, unless I want to duplicate the code. Any ideas?

解决方案

move your "do stuff with r" block into your $.getJSON callback. you can't do stuff with r until it has been delivered, and the first opportunity you'll have to use r is in the callback... so do it then.

$(function() {
    var r = GetResults();  
});

function GetResults() {
   $.getJSON("/controller/method/", null, function(data) {
       for(var i = 0; i < data.length; i++) {
           // Do stuff with data
       }
       return data;
   });
}

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