在 jQuery 的 Deferred 对象中抛出错误 [英] Throwing an Error in jQuery's Deferred object

问题描述

我有一个 $.ajax 承诺并且想要检查我的(语法上有效的)响应是否包含错误，在这种情况下触发拒绝状态.

I have an $.ajax promise and want to check whether my (syntactically valid) response contains an error, triggering the rejected status in that case.

我使用了自己的 Promise 库，可以轻松处理此类任务.我不太喜欢 jQuery 的 Promise (cache) 实现及其 Deferred object 并且可能忽略了一些东西，因为我很少使用它.我认为要走的路只是使用 .then()，这似乎相当复杂:

I have worked with my own promise library which deals such tasks easily. I do not really like jQuery's Promise (cache) implementation with its Deferred object and may have overlooked something, because I seldom use it. I think the way to go is just using .then(), which seems to be rather complicated:

return $.ajax(...).then(function success(response) {
    var problem = hasError(response);
    if (problem) {
        var error = new $.Deferred;
        error.reject(problem);
        return error;
    } else
        return response;
});

这应该返回一个承诺，在出现网络错误或响应问题时被拒绝.但是返回一个被拒绝的 deferred 真的是 [only|best|shortest] 方法吗?

This should return a promise which is rejected in case of network errors or problems with the response. But is returning a rejected deferred really the [only|best|shortest] way to go?

我也会在 ajax 选项本身中提供有关如何处理此类错误抛出响应处理程序"的帮助，我找不到关于它们的良好文档.

I also would appriciate help on how to deal with such "error-throwing response handlers" in the ajax options themselfes, I could not find good documentation about them.

免责声明:不，我无法更改服务器响应.问题检测方法是同步的.我不想使用其他库，我对 jQuery 解决这个问题的方式特别感兴趣.

Disclaimer: No, I cant change the server responses. The problem-detecting method is synchronous. I don't want to use other libraries, I'm particularly interested in the way jQuery solves this.

推荐答案

现已针对 jQuery 1.8+ 进行更新

解决这个问题的最简单方法是运行 $.ajax 到 .then 的响应，以根据数据的成功或失败进行过滤.

The easiest way to tackle this is to run the response of $.ajax through .then to filter based on success or failure of the data.

$.ajax()
    .then(function (response) {
        return $.Deferred(function (deferred) {
            var problem = hasError(response);

            if (problem) {
                return deferred.reject(problem)
            }

            deferred.resolve(response);
        }).promise();
    });

然后，您可以将这个新承诺返回给任何调用代码将使用它:

You could then return this new promise to whatever calling code would consume this:

var request = function () {
    return $.ajax()
        .then(function (response) {
            return $.Deferred(function (deferred) {
                var problem = hasError(response);

                if (problem) {
                    return deferred.reject(problem)
                }

                deferred.resolve(response);
            }).promise();
        });
};

request()
    .done(function (response) {
        // handle success
    })
    .fail(function (problem) {
        // handle failure
    });

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