javascript 带有嵌套 ajax 调用的 jQuery 延迟对象
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jQuery deferred object with nested ajax calls
提问by Aesthete
I have a situation in which my ajax calls must perform in a particular order. I have used jQuery Deferred objects in other situations, but cannot seem to find a way to make this behave appropriately.
我有一种情况，我的 ajax 调用必须按特定顺序执行。我在其他情况下使用过 jQuery Deferred 对象，但似乎无法找到一种方法来使其行为适当。
I have a function which performs a number of ajaxrequests in it's lifetime. Some of the requests will be performed during the success callback of other requests.
我有一个函数，它ajax在它的生命周期中执行许多请求。某些请求会在其他请求成功回调期间执行。
My question: is there a way to return all nested deferred objects to the original $.whencall?
我的问题：有没有办法将所有嵌套的延迟对象返回到原始$.when调用？
A simplified example would be:
一个简化的例子是：
function nestedAjax() {
$.get("/", function(){
console.log("First ajax done.");
$.get("/", function(){
console.log("Second ajax done.");
});
});
};
I am trying to have the nestedAjaxfunction to use $.when()and $.done()like so:
我正在尝试nestedAjax使用该功能，$.when()并且$.done()喜欢这样：
$.when(nestedAjax()).done(function(){
console.log("Complete");
});?
With the console output reading:
随着控制台输出读数：
> First ajax done.
> Second ajax done.
> Complete.
I can return the first getto achieve this:
我可以返回第一个get来实现这一点：
> First ajax done.
> Complete.
> Second ajax done.
But obviously this is not what I require. Any help would be appreciated.
但显然这不是我所需要的。任何帮助，将不胜感激。
采纳答案by DrColossos
It's actually quite simple. Though all the AJAX calls are Deferred objects, I still use one for the method itself.
其实很简单。尽管所有 AJAX 调用都是 Deferred 对象，但我仍然为方法本身使用一个。
function nestedAjax() {
var dfd = $.Deferred();
$.get("/echo/json/", function(){
console.log("First ajax done.");
$.get("/echo/json/", function(){
console.log("Second ajax done.");
dfd.resolve();
});
});
return dfd.promise();
};
回答by dmnd
You don't actually need an extra deferred object. You can do what you want by chaining with then():
您实际上并不需要额外的延迟对象。你可以通过链接来做你想做的事then()：
function nestedAjax() {
return $.get("/echo/json/").then(function(result1){
console.log("First ajax done.");
if (result1) {
return result1;
} else {
return $.get("/echo/json/").then(function(nestedResult){
console.log("Second ajax done.");
return nestedResult;
});
}
});
};
I added some logic since I think that's probably the reason you are executing this synchronously. After that you can use the result in $.whenlike so:
我添加了一些逻辑，因为我认为这可能是您同步执行此操作的原因。之后，您可以$.when像这样使用结果：
$.when(nestedAjax(), $.get("/something/else")).then(function(nested, other) {
console.log("Complete.", nested, other);
});
回答by Juw
Couldn′t add a comment for some reason to the above answer.
由于某种原因无法对上述答案添加评论。
So i add my comment here. The above answer will only work if the ajax calls are fast and returns BEFORE the return dfd.promise().
所以我在这里添加我的评论。上面的答案只有在 ajax 调用很快并且在返回 dfd.promise() 之前返回时才有效。
I have the same problem. And as you can see. The returned deferred object states that it is "pending": http://jsfiddle.net/BtEKa/
我也有同样的问题。正如你所看到的。返回的延迟对象表明它是“待处理的”：http: //jsfiddle.net/BtEKa/
