为什么我最后在JSON中获得了额外的元素？ [英] Why do I get an extra element at the end in JSON?

问题描述

我正在使用某个网站，并且正在使用JSON。我的问题是JSON.parse方法，我用它来发送一个简单的数组，并将值附加到数组中。我总是得到一个额外的元素，我们只是逗号。这是简化的代码：

I'm working on some website, and am using JSON. My problem is the JSON.parse method, I use it to send a simple array, and append to an array the values. And I always get an extra element at the end that us just commas. here is the simplified code:

responseText = '["dummy1", "dummy2", "dummy3", "dummy4"]';
var  clientList=[];
try {
    JSON.parse(responseText, function(key, val){clientList.push(val)});
} catch (e) {
    alert('no');
}

alert(clientList.length);

首先在IE中它根本不起作用（抛出异常）。

First in IE its not working at all (exception is thrown).

第二个chrome结果是clientList是一个包含5个字符串的数组，而最后一个是',,,'。

Second chrome the result is that clientList is an array of 5 strings, while the last one is ',,, '.

为什么是那里有额外的价值吗？我可以摆脱它（不只是在最后弹出阵列）？ IE有什么问题？

Why is that extra value there? Can I get rid of it (without just popping the array at the end)? And what is wrong with IE?

推荐答案

这样可行：

responseText = '["dummy1", "dummy2", "dummy3", "dummy4"]';
var  clientList=[];
try {
    clientList = JSON.parse(responseText);
} catch (e) {
    alert('no');
}

IE没有 JSON 作为浏览器的默认值。你需要一个像json2这样的库。

IE doesn't have JSON as a default in the browser. You need a library like json2.

至于你的问题，那个回调函数实际上是为了转换你的对象而不是构建它。例如：

As for your question, that callback function is really in order to transform your object not build it. For example:

var transformed =
JSON.parse('{"p": 5}', function(k, v) { if (k === "") return v; return v * 2; });
// transformed is { p: 10 }

来自解析

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