blocks|key|5191093|text|只要您能保证一个相当现代的浏览器，JSON.parse(jsonString)就是一种纯粹的JavaScript方法。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5191094|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse^0|H|M|H|M|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]]|D|@$9|Q|A|R|1|S]]|E|$]]|$1|F|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

<a href="https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse" rel="noreferrer"><code>JSON.parse(jsonString)</code></a> is a pure JavaScript approach so long as you can guarantee a reasonably modern browser.

blocks|key|2935327|text|jQuery方法现在已弃用。请改用此方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2935328|let+jsonObject+=+JSON.parse(jsonString);|code-block|syntax|javascript|2935329|2935330|使用不推荐使用的jQuery功能的原始答案|2935331|如果您使用的是jQuery，只需使用：|2935332|jQuery.parseJSON(+jsonString+);|2935333|这正是您正在寻找的(请参阅jQuery+documentation)。|offset|length|2935334|entityMap|0|LINK|mutability|MUTABLE|url|http://api.jquery.com/jQuery.parseJSON/^0|0|0|0|0|0|0|K|D|0|0^^$0|@$1|2|3|4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|10|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|11|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|12|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|13|8|@]|9|@]|A|$]]|$1|L|3|M|5|D|7|14|8|@]|9|@]|A|$E|F]]|$1|N|3|O|5|6|7|15|8|@]|9|@$P|16|Q|17|1|18]]|A|$]]|$1|R|3|-4|5|6|7|19|8|@]|9|@]|A|$]]]|S|$T|$5|U|V|W|A|$X|Y]]]]

The jQuery method is now deprecated. Use this method instead:

<pre><code>let jsonObject = JSON.parse(jsonString);
</code></pre>

<hr>

Original answer using deprecated jQuery functionality:

If you're using jQuery just use:

<pre><code>jQuery.parseJSON( jsonString );
</code></pre>

It's exactly what you're looking for (see the jQuery <a href="http://api.jquery.com/jQuery.parseJSON/" rel="noreferrer">documentation</a>).

blocks|key|3780339|text|这个答案是针对IE+<+7的，对于现代浏览器，请查看上面Jonathan的答案。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3780340|这个答案已经过时了，+(JSON.parse(jsonString))现在是最好的答案。|offset|length|style|BOLD|CODE|3780341|JSON.org有多种语言的JSON解析器，包括四种不同的JavaScript解析器。我相信大多数人会认为json2.js是他们的goto实现。|3780342|entityMap|0|LINK|mutability|MUTABLE|url|http://json.org/|1|http://www.json.org/js.html^0|0|C|M|C|M|0|0|8|0|1H|8|1|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@$D|W|E|X|F|G]|$D|Y|E|Z|F|H]]|9|@]|A|$]]|$1|I|3|J|5|6|7|10|8|@]|9|@$D|11|E|12|1|13]|$D|14|E|15|1|16]]|A|$]]|$1|K|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]|S|$5|N|O|P|A|$Q|T]]]]

This answer is for IE &lt; 7, for modern browsers check Jonathan's answer above.

This answer is outdated and <a href="https://stackoverflow.com/a/5686237/542251">Jonathan's answer above</a> (<code>JSON.parse(jsonString)</code>) is now the best answer.

<a href="http://json.org/" rel="noreferrer">JSON.org</a> has JSON parsers for many languages including four different ones for JavaScript. I believe most people would consider <a href="http://www.json.org/js.html" rel="noreferrer">json2.js</a> their goto implementation.

blocks|key|725357|text|使用“JSON.parse()”中的简单代码示例：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|725358|var+jsontext+=+'{"firstname":"Jesper","surname":"Aaberg","phone":["555-0100","555-0120"]}';
var+contact+=+JSON.parse(jsontext);|code-block|syntax|javascript|725359|并颠倒过来：|725360|var+str+=+JSON.stringify(arr);|725361|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/ie/cc836466%2528v=vs.94%2529.aspx^0|3|C|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

Use the simple code example in "<a href="http://msdn.microsoft.com/en-us/library/ie/cc836466%28v=vs.94%29.aspx" rel="noreferrer">JSON.parse()</a>":

<pre><code>var jsontext = '{"firstname":"Jesper","surname":"Aaberg","phone":["555-0100","555-0120"]}';
var contact = JSON.parse(jsontext);
</code></pre>

and reversing it:

<pre><code>var str = JSON.stringify(arr);
</code></pre>

blocks|key|3780606|text|这似乎就是问题所在：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3780607|通过Ajax+websocket等接收的输入，它将是字符串格式，但您需要知道它是否是JSON.parsable。问题是，如果你总是通过JSON.parse运行它，程序可能会“成功”地继续运行，但你仍然会在控制台中看到一个带有可怕的"Error:+unexpected+token+'x'"的错误抛出。|offset|length|style|CODE|3780608|var+data;

try+{
++data+=+JSON.parse(jqxhr.responseText);
}+catch+(_error)+{}

data+%7C%7C+(data+=+{
++message:+'Server+error,+please+retry'
});|code-block|syntax|javascript|3780609|entityMap^0|0|16|D|1V|A|37|T|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@$D|Q|E|R|F|G]|$D|S|E|T|F|G]|$D|U|E|V|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|W|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|N|$]]

This seems to be the issue:

An input that is received via Ajax websocket etc, and it will be in String format, but you need to know if it is <code>JSON.parsable</code>. The touble is, if you always run it through <code>JSON.parse</code>, the program MAY continue "successfully" but you'll still see an error thrown in the console with the dreaded <code>"Error: unexpected token 'x'"</code>.

<pre><code>var data;

try {
 data = JSON.parse(jqxhr.responseText);
} catch (_error) {}

data || (data = {
 message: 'Server error, please retry'
});
</code></pre>

blocks|key|5190784|text|我不确定是否有其他方法可以做到这一点，但下面是你在Prototype+(JSON+tutorial)中如何做到这一点。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|5190785|new+Ajax.Request('/some_url',+{
++method:'get',
++requestHeaders:+{Accept:+'application/json'},
++onSuccess:+function(transport){
++++var+json+=+transport.responseText.evalJSON(true);
++}
});|code-block|syntax|javascript|5190786|以true作为参数调用evalJSON()将清理传入的字符串。|style|CODE|5190787|entityMap|0|LINK|mutability|MUTABLE|url|http://www.prototypejs.org/learn/json^0|P|P|0|0|0|B|A|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@$A|10|B|11|K|L]]|9|@]|C|$]]|$1|M|3|-4|5|6|7|12|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

I'm not sure about other ways to do it but here's how you do it in <a href="http://www.prototypejs.org/learn/json" rel="nofollow noreferrer">Prototype (JSON tutorial)</a>.

<pre><code>new Ajax.Request('/some_url', {
 method:'get',
 requestHeaders: {Accept: 'application/json'},
 onSuccess: function(transport){
 var json = transport.responseText.evalJSON(true);
 }
});
</code></pre>

Calling <code>evalJSON()</code> with true as the argument sanitizes the incoming string.

blocks|key|5190938|text|如果你使用的是jQuery，你也可以使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|5190939|$.getJSON(url,+function(data)+{+});|code-block|syntax|javascript|5190940|然后你可以做像这样的事情|5190941|data.key1.something
data.key1.something_else|5190942|等。|5190943|entityMap|0|LINK|mutability|MUTABLE|url|https://jquery.com/^0|7|6|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|11|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|12|8|@]|9|@]|C|$G|H]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|C|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]]]

If you're using <a href="https://jquery.com/" rel="noreferrer">jQuery</a>, you can also use:

<pre><code>$.getJSON(url, function(data) { });
</code></pre>

Then you can do things like

<pre><code>data.key1.something
data.key1.something_else
</code></pre>

etc.

blocks|key|3780744|text|为了好玩，这里有一种使用函数的方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3780745|+jsonObject+=+(new+Function('return+'+%2B+jsonFormatData))()|code-block|syntax|javascript|3780746|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Just for fun, here is a way using a function:

<pre><code> jsonObject = (new Function('return ' + jsonFormatData))()
</code></pre>

blocks|key|5191002|text|$.ajax({
++url:+url,
++dataType:+'json',
++data:+data,
++success:+callback
});|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|5191003|向回调传递返回的数据，该数据将是由JSON结构定义的JavaScript对象或数组，并使用$.parseJSON()方法进行解析。|unstyled|offset|length|style|CODE|5191004|entityMap^0|0|19|D|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|N|8|@$G|O|H|P|I|J]]|9|@]|A|$]]|$1|K|3|-4|5|F|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<pre><code>$.ajax({
 url: url,
 dataType: 'json',
 data: data,
 success: callback
});
</code></pre>

The callback is passed the returned data, which will be a JavaScript object or array as defined by the JSON structure and parsed using the <code>$.parseJSON()</code> method.

blocks|key|720357|text|使用JSON.parse可能是最好的方法。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|720358|下面是一个例子|720359|var+jsonRes+=+'{+"students"+:+['+%2B
++++++++++'{+"firstName":"Michel"+,+"lastName":"John"+,"age":18},'+%2B
++++++++++'{+"firstName":"Richard"+,+"lastName":"Joe","age":20+},'+%2B
++++++++++'{+"firstName":"James"+,+"lastName":"Henry","age":15+}+]}';
var+studentObject+=+JSON.parse(jsonRes);|code-block|syntax|javascript|720360|entityMap^0|2|A|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|R|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|S|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

Using <code>JSON.parse</code> is probably the best way.
Here's an example
<pre><code>var jsonRes = '{ &quot;students&quot; : [' +
 '{ &quot;firstName&quot;:&quot;Michel&quot; , &quot;lastName&quot;:&quot;John&quot; ,&quot;age&quot;:18},' +
 '{ &quot;firstName&quot;:&quot;Richard&quot; , &quot;lastName&quot;:&quot;Joe&quot;,&quot;age&quot;:20 },' +
 '{ &quot;firstName&quot;:&quot;James&quot; , &quot;lastName&quot;:&quot;Henry&quot;,&quot;age&quot;:15 } ]}';
var studentObject = JSON.parse(jsonRes);
</code></pre>

blocks|key|720311|text|尝试对此数据对象使用该方法。例如：Data='{result:true,count:1}‘|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|720312|try+{
++eval('var+obj='+%2B+Data);
++console.log(obj.count);
}
catch(e)+{
++console.log(e.message);
}|code-block|syntax|javascript|720313|当您使用串口编程时，这种方法在Nodejs中非常有用。|720314|entityMap^0|H|R|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

Try using the method with this Data object. ex:<code>Data='{result:true,count:1}</code>'

<pre><code>try {
 eval('var obj=' + Data);
 console.log(obj.count);
}
catch(e) {
 console.log(e.message);
}
</code></pre>

This method really helps in Nodejs when you are working with serial port programming

blocks|key|3780837|text|使用parse()方法的最简单方法：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3780838|var+response+=+'{"result":true,"count":1}';
var+JsonObject=+JSON.parse(response);|code-block|syntax|javascript|3780839|然后，您可以获得JSON元素的值，例如：|3780840|var+myResponseResult+=+JsonObject.result;
var+myResponseCount+=+JsonObject.count;|3780841|按照jQuery.parseJSON()文档中的说明使用jQuery：|3780842|JSON.parse(jsonString);|3780843|entityMap|0|LINK|mutability|MUTABLE|url|http://api.jquery.com/jQuery.parseJSON/|1|http://jquery.com/^0|2|7|0|0|0|0|2|I|2|I|0|S|6|1|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|15|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|16|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|17|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|18|8|@$9|19|A|1A|B|C]]|D|@$9|1B|A|1C|1|1D]|$9|1E|A|1F|1|1G]]|E|$]]|$1|Q|3|R|5|H|7|1H|8|@]|D|@]|E|$I|J]]|$1|S|3|-4|5|6|7|1I|8|@]|D|@]|E|$]]]|T|$U|$5|V|W|X|E|$Y|Z]]|10|$5|V|W|X|E|$Y|11]]]]

The easiest way using <code>parse()</code> method:

<pre><code>var response = '{"result":true,"count":1}';
var JsonObject= JSON.parse(response);
</code></pre>

Then you can get the values of the JSON elements, for example:

<pre><code>var myResponseResult = JsonObject.result;
var myResponseCount = JsonObject.count;
</code></pre>

Using <a href="http://jquery.com/" rel="nofollow noreferrer">jQuery</a> as described in the <a href="http://api.jquery.com/jQuery.parseJSON/" rel="nofollow noreferrer"><code>jQuery.parseJSON()</code></a> documentation:

<pre><code>JSON.parse(jsonString);
</code></pre>

blocks|key|5191317|text|我找到了一个“更好”的方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5191318|在CoffeeScript中：|5191319|try+data+=+JSON.parse(jqxhr.responseText)
data+%7C%7C=+{+message:+'Server+error,+please+retry'+}|code-block|syntax|javascript|5191320|在Javascript中：|5191321|var+data;

try+{
++data+=+JSON.parse(jqxhr.responseText);
}+catch+(_error)+{}

data+%7C%7C+(data+=+{
++message:+'Server+error,+please+retry'
});|5191322|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I found a "better" way:

In CoffeeScript:

<pre><code>try data = JSON.parse(jqxhr.responseText)
data ||= { message: 'Server error, please retry' }
</code></pre>

In Javascript:

<pre><code>var data;

try {
 data = JSON.parse(jqxhr.responseText);
} catch (_error) {}

data || (data = {
 message: 'Server error, please retry'
});
</code></pre>

blocks|key|720407|text|JSON解析总是一件痛苦的事情。如果输入不是预期的，它会抛出一个错误，并使您正在做的事情崩溃。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|720408|您可以使用下面的小函数来安全地解析您的输入。它总是转换对象，即使输入无效或已经是对象，这在大多数情况下是更好的：|720409|JSON.safeParse+=+function+(input,+def)+{
++//+Convert+null+to+empty+object
++if+(!input)+{
++++return+def+%7C%7C+{};
++}+else+if+(Object.prototype.toString.call(input)+===+'[object+Object]')+{
++++return+input;
++}
++try+{
++++return+JSON.parse(input);
++}+catch+(e)+{
++++return+def+%7C%7C+{};
++}
};|code-block|syntax|javascript|720410|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

JSON parsing is always a pain. If the input is not as expected it throws an error and crashes what you are doing. 

You can use the following tiny function to safely parse your input. It always turns an object even if the input is not valid or is already an object which is better for most cases:

<pre><code>JSON.safeParse = function (input, def) {
 // Convert null to empty object
 if (!input) {
 return def || {};
 } else if (Object.prototype.toString.call(input) === '[object Object]') {
 return input;
 }
 try {
 return JSON.parse(input);
 } catch (e) {
 return def || {};
 }
};
</code></pre>

blocks|key|5191409|text|JSON.parse(jsonString);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|5191410|json.parse将变为object。|unstyled|5191411|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>JSON.parse(jsonString);
</code></pre>

json.parse will change into object.

blocks|key|3781048|text|官方文档|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|3781049|JSON.parse()方法解析JSON字符串，构造由该字符串描述的JSON值或对象。可以提供一个可选的reviver函数，以便在返回结果对象之前对其执行转换。|CODE|3781050|语法：|3781051|JSON.parse(text[,+reviver])|code-block|syntax|javascript|3781052|参数：|3781053|JSON+:要解析为text的字符串。有关JSON语法的描述，请参阅JSON对象。|3781054|reviver+(optional)：如果是一个函数，则指定在返回之前如何转换最初由解析生成的值。|3781055|返回值|3781056|与给定JSON文本相对应的对象。|3781057|Exceptions|3781058|如果要解析的字符串不是有效的SyntaxError，则引发JSON异常。|3781059|entityMap^0|0|4|0|0|C|1G|7|0|0|3|0|0|0|3|0|A|4|0|0|I|0|0|3|0|0|0|A|0|0^^$0|@$1|2|3|4|5|6|7|15|8|@$9|16|A|17|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|18|8|@$9|19|A|1A|B|H]|$9|1B|A|1C|B|H]]|D|@]|E|$]]|$1|I|3|J|5|6|7|1D|8|@$9|1E|A|1F|B|C]]|D|@]|E|$]]|$1|K|3|L|5|M|7|1G|8|@]|D|@]|E|$N|O]]|$1|P|3|Q|5|6|7|1H|8|@$9|1I|A|1J|B|C]]|D|@]|E|$]]|$1|R|3|S|5|6|7|1K|8|@$9|1L|A|1M|B|H]]|D|@]|E|$]]|$1|T|3|U|5|6|7|1N|8|@$9|1O|A|1P|B|H]]|D|@]|E|$]]|$1|V|3|W|5|6|7|1Q|8|@$9|1R|A|1S|B|C]]|D|@]|E|$]]|$1|X|3|Y|5|6|7|1T|8|@]|D|@]|E|$]]|$1|Z|3|10|5|6|7|1U|8|@$9|1V|A|1W|B|C]]|D|@]|E|$]]|$1|11|3|12|5|6|7|1X|8|@]|D|@]|E|$]]|$1|13|3|-4|5|6|7|1Y|8|@]|D|@]|E|$]]]|14|$]]

Official documentation:

The <code>JSON.parse()</code> method parses a JSON string, constructing the JavaScript value or object described by the string. An optional <code>reviver</code> function can be provided to perform a transformation on the resulting object before it is returned.

Syntax:

<pre><code>JSON.parse(text[, reviver])
</code></pre>

Parameters:

<code>text</code>
: The string to parse as JSON. See the JSON object for a description of JSON syntax.

<code>reviver (optional)</code>
: If a function, this prescribes how the value originally produced by parsing is transformed, before being returned.

Return value

The Object corresponding to the given JSON text.

Exceptions

Throws a SyntaxError exception if the string to parse is not valid JSON.

blocks|key|3781217|text|用JSON.parse()解析JSON字符串，数据变成JavaScript对象：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3781218|JSON.parse(jsonString)|code-block|syntax|javascript|3781219|这里，JSON表示处理JSON数据集。|3781220|假设我们从web服务器收到以下文本：|3781221|'{+"name":"John",+"age":30,+"city":"New+York"}'|3781222|要解析为JSON对象，请执行以下操作：|3781223|var+obj+=+JSON.parse('{+"name":"John",+"age":30,+"city":"New+York"}');+|3781224|这里的obj是各自的JSON对象，如下所示：|3781225|{+"name":"John",+"age":30,+"city":"New+York"}|3781226|要获取值，请使用.运算符：|3781227|obj.name+//+John
obj.age+//30|3781228|使用JSON.stringify()将JavaScript对象转换为字符串。|3781229|entityMap^0|1|C|0|0|0|0|0|0|0|3|3|0|0|8|1|0|0|2|G|0^^$0|@$1|2|3|4|5|6|7|16|8|@$9|17|A|18|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|19|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1A|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|1B|8|@]|D|@]|E|$]]|$1|O|3|P|5|H|7|1C|8|@]|D|@]|E|$I|J]]|$1|Q|3|R|5|6|7|1D|8|@]|D|@]|E|$]]|$1|S|3|T|5|H|7|1E|8|@]|D|@]|E|$I|J]]|$1|U|3|V|5|6|7|1F|8|@$9|1G|A|1H|B|C]]|D|@]|E|$]]|$1|W|3|X|5|H|7|1I|8|@]|D|@]|E|$I|J]]|$1|Y|3|Z|5|6|7|1J|8|@$9|1K|A|1L|B|C]]|D|@]|E|$]]|$1|10|3|11|5|H|7|1M|8|@]|D|@]|E|$I|J]]|$1|12|3|13|5|6|7|1N|8|@$9|1O|A|1P|B|C]]|D|@]|E|$]]|$1|14|3|-4|5|6|7|1Q|8|@]|D|@]|E|$]]]|15|$]]

Parse the JSON string with <code>JSON.parse()</code>, and the data becomes a JavaScript object:

<pre><code>JSON.parse(jsonString)
</code></pre>

Here, JSON represents to process JSON dataset.

Imagine we received this text from a web server:

<pre><code>'{ "name":"John", "age":30, "city":"New York"}'
</code></pre>

To parse into a JSON object:

<pre><code>var obj = JSON.parse('{ "name":"John", "age":30, "city":"New York"}'); 
</code></pre>

Here <code>obj</code> is the respective JSON object which looks like:

<pre><code>{ "name":"John", "age":30, "city":"New York"}
</code></pre>

To fetch a value use the <code>.</code> operator:

<pre><code>obj.name // John
obj.age //30
</code></pre>

Convert a JavaScript object into a string with <code>JSON.stringify()</code>.

blocks|key|5191974|text|如果我们有一个这样的字符串：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5191975|"{\"status\":1,\"token\":\"65b4352b2dfc4957a09add0ce5714059\"}"|code-block|syntax|javascript|5191976|然后，我们可以简单地使用JSON.parse两次将该字符串转换为JSON对象：|offset|length|style|CODE|5191977|var+sampleString+=+"{\"status\":1,\"token\":\"65b4352b2dfc4957a09add0ce5714059\"}"
var+jsonString=+JSON.parse(sampleString)
var+jsonObject=+JSON.parse(jsonString)|5191978|我们可以使用以下命令从JSON对象中提取值：|5191979|//+instead+of+last+JSON.parse:
var+{+status,+token+}+=+JSON.parse(jsonString);|5191980|结果将是：|5191981|status+=+1+and+token+=+65b4352b2dfc4957a09add0ce5714059|5191982|entityMap^0|0|0|C|A|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|10|8|@$I|11|J|12|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|14|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|15|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|16|8|@]|9|@]|A|$]]|$1|U|3|V|5|D|7|17|8|@]|9|@]|A|$E|F]]|$1|W|3|-4|5|6|7|18|8|@]|9|@]|A|$]]]|X|$]]

If we have a string like this:

<pre><code>"{\"status\":1,\"token\":\"65b4352b2dfc4957a09add0ce5714059\"}"
</code></pre>

then we can simply use <code>JSON.parse</code> twice to convert this string to a JSON object:

<pre><code>var sampleString = "{\"status\":1,\"token\":\"65b4352b2dfc4957a09add0ce5714059\"}"
var jsonString= JSON.parse(sampleString)
var jsonObject= JSON.parse(jsonString)
</code></pre>

And we can extract values from the JSON object using:

<pre><code>// instead of last JSON.parse:
var { status, token } = JSON.parse(jsonString);
</code></pre>

The result will be:

<pre><code>status = 1 and token = 65b4352b2dfc4957a09add0ce5714059
</code></pre>

blocks|key|5191489|text|将对象转换为JSON，然后对其进行解析，对我来说是可行的，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5191490|JSON.parse(JSON.stringify(object))|code-block|syntax|javascript|5191491|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Converting the object to JSON, and then parsing it, works for me, like:

<pre><code>JSON.parse(JSON.stringify(object))
</code></pre>

blocks|key|3781465|text|只需对不同输入类型进行封面解析|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3781466|用JSON.parse()解析数据，数据就变成了JavaScript对象。|3781467|var+obj+=+JSON.parse('{+"name":"John",+"age":30,+"city":"New+York"}');|code-block|syntax|javascript|3781468|在从数组派生的JSON上使用JSON.parse()时，该方法将返回JavaScript数组，而不是JavaScript对象。|3781469|var+myArr+=+JSON.parse(this.responseText);
console.log(myArr[0]);|3781470|JSON中不允许使用Date对象。因为约会就是这样的|3781471|var+text+=+'{+"name":"John",+"birth":"1986-12-14",+"city":"New+York"}';
var+obj+=+JSON.parse(text);
obj.birth+=+new+Date(obj.birth);|3781472|JSON中不允许使用函数。如果你需要包含一个函数，把它写成一个字符串。|3781473|var+text+=+'{+"name":"John",+"age":"function+()+{return+30;}",+"city":"New+York"}';
var+obj+=+JSON.parse(text);
obj.age+=+eval("("+%2B+obj.age+%2B+")");|3781474|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|11|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|12|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|13|8|@]|9|@]|A|$]]|$1|S|3|T|5|F|7|14|8|@]|9|@]|A|$G|H]]|$1|U|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|V|$]]

Just to the cover parse for different input types

Parse the data with JSON.parse(), and the data becomes a JavaScript object.

<pre><code>var obj = JSON.parse('{ "name":"John", "age":30, "city":"New York"}');
</code></pre>

When using the JSON.parse() on a JSON derived from an array, the method will return a JavaScript array, instead of a JavaScript object.

<pre><code>var myArr = JSON.parse(this.responseText);
console.log(myArr[0]);
</code></pre>

Date objects are not allowed in JSON.
For Dates do somthing like this

<pre><code>var text = '{ "name":"John", "birth":"1986-12-14", "city":"New York"}';
var obj = JSON.parse(text);
obj.birth = new Date(obj.birth);
</code></pre>

Functions are not allowed in JSON.
If you need to include a function, write it as a string.

<pre><code>var text = '{ "name":"John", "age":"function () {return 30;}", "city":"New York"}';
var obj = JSON.parse(text);
obj.age = eval("(" + obj.age + ")");
</code></pre>

blocks|key|2935861|text|您也可以使用reviver函数进行过滤。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2935862|var+data+=+JSON.parse(jsonString,+function+reviver(key,+value)+{
+++//your+code+here+to+filter
});|code-block|syntax|javascript|2935863|有关更多信息，请阅读JSON.parse。|2935864|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse^0|6|7|0|0|A|A|A|A|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@$9|Z|A|10|B|C]]|D|@$9|11|A|12|1|13]]|E|$]]|$1|M|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

You also can use <code>reviver</code> function to filter.

<pre><code>var data = JSON.parse(jsonString, function reviver(key, value) {
 //your code here to filter
});
</code></pre>

For more information read <a href="https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse" rel="nofollow noreferrer"><code>JSON.parse</code></a>.

blocks|key|5191697|text|老问题，我知道，但是没有人注意到这个解决方案，使用new+Function()，一个返回数据的匿名函数。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5191698|5191699|举个例子：|5191700|+var+oData+=+'test1:"This+is+my+object",test2:"This+is+my+object"';

+if(+typeof+oData+!==+'object'+)
++try+{
+++oData+=+(new+Function('return+{'%2BoData%2B'};'))();
++}
++catch(e)+{+oData=false;+}

+if(+typeof+oData+!==+'object'+)
++{+alert(+'Error+in+code'+);+}
+else+{
++++++++alert(+oData.test1+);
++++++++alert(+oData.test2+);
++++++}|code-block|syntax|javascript|5191701|5191702|这更安全一些，因为它在函数中执行，而不是直接在代码中编译。因此，如果其中有一个函数声明，它将不会被绑定到默认的窗口对象。|5191703|我使用它来简单快速地“编译”DOM元素的配置设置(例如data属性)。|5191704|entityMap^0|P|E|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|X|8|@]|D|@]|E|$]]|$1|G|3|H|5|6|7|Y|8|@]|D|@]|E|$]]|$1|I|3|J|5|K|7|Z|8|@]|D|@]|E|$L|M]]|$1|N|3|-4|5|6|7|10|8|@]|D|@]|E|$]]|$1|O|3|P|5|6|7|11|8|@]|D|@]|E|$]]|$1|Q|3|R|5|6|7|12|8|@]|D|@]|E|$]]|$1|S|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|T|$]]

Older question, I know, however nobody notice this solution by using <code>new Function()</code>, an anonymous function that returns the data. 

<hr>

Just an example:

<pre><code> var oData = 'test1:"This is my object",test2:"This is my object"';

 if( typeof oData !== 'object' )
 try {
 oData = (new Function('return {'+oData+'};'))();
 }
 catch(e) { oData=false; }

 if( typeof oData !== 'object' )
 { alert( 'Error in code' ); }
 else {
 alert( oData.test1 );
 alert( oData.test2 );
 }
</code></pre>

<hr>

This is a little more safe because it executes inside a function and do not compile in your code directly. So if there is a function declaration inside it, it will not be bound to the default window object. 

I use this to 'compile' configuration settings of DOM elements (for example the data attribute) simple and fast.

blocks|key|5191899|text|摘要：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5191900|Javascript+(浏览器和NodeJS)都有一个内置的JSON对象。在这个对象上有两个处理JSON的方便方法。它们如下所示：|offset|length|style|CODE|5191901|5191902|JSON.parse()以JSON为参数，返回JS+object|ordered-list-item|5191903|JSON.stringify()以JS+object为参数返回JSON+object|5191904|5191905|其他应用程序：|5191906|此外，为了非常方便地处理JSON，它们还可以用于其他方式。这两种JSON方法的结合使我们可以非常容易地对数组或对象进行深度克隆。例如：|5191907|​|5191908|let+arr1+=+[1,+2,+[3+,4]];
let+newArr+=+arr1.slice();

arr1[2][0]+=+'changed';+
console.log(newArr);+//+not+a+deep+clone

let+arr2+=+[1,+2,+[3+,4]];
let+newArrDeepclone+=+JSON.parse(JSON.stringify(arr2));

arr2[2][0]+=+'changed';+
console.log(newArrDeepclone);+//+A+deep+clone,+values+unchanged|code-block|syntax|javascript|5191909|5191910|entityMap^0|0|U|4|1C|4|0|0|0|C|D|4|0|0|G|V|4|0|0|0|C|4|W|4|0|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|13|8|@$D|14|E|15|F|G]|$D|16|E|17|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|18|8|@]|9|@]|A|$]]|$1|I|3|J|5|K|7|19|8|@$D|1A|E|1B|F|G]|$D|1C|E|1D|F|G]]|9|@]|A|$]]|$1|L|3|M|5|K|7|1E|8|@$D|1F|E|1G|F|G]|$D|1H|E|1I|F|G]]|9|@]|A|$]]|$1|N|3|-4|5|6|7|1J|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|1K|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1L|8|@$D|1M|E|1N|F|G]|$D|1O|E|1P|F|G]]|9|@]|A|$]]|$1|S|3|T|5|6|7|1Q|8|@]|9|@]|A|$]]|$1|U|3|V|5|W|7|1R|8|@]|9|@]|A|$X|Y]]|$1|Z|3|T|5|6|7|1S|8|@]|9|@]|A|$]]|$1|10|3|-4|5|6|7|1T|8|@]|9|@]|A|$]]]|11|$]]

<h2>Summary:</h2>

Javascript (both browser and NodeJS) have a built in <code>JSON</code> object. On this Object are 2 convenient methods for dealing with <code>JSON</code>. They are the following:

<ol>
<li><code>JSON.parse()</code> Takes <code>JSON</code> as argument, returns JS object</li>
<li><code>JSON.stringify()</code> Takes JS object as argument returns <code>JSON</code> object</li>
</ol>

<h2>Other applications:</h2>

Besides for very conveniently dealing with <code>JSON</code> they have can be used for other means. The combination of both <code>JSON</code> methods allows us to make very easy make deep clones of arrays or objects. For example:

<div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>let arr1 = [1, 2, [3 ,4]];
let newArr = arr1.slice();

arr1[2][0] = 'changed'; 
console.log(newArr); // not a deep clone

let arr2 = [1, 2, [3 ,4]];
let newArrDeepclone = JSON.parse(JSON.stringify(arr2));

arr2[2][0] = 'changed'; 
console.log(newArrDeepclone); // A deep clone, values unchanged</code></pre>
</div>
</div>

blocks|key|5192247|text|性能|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5192248|这个问题已经有了很好的答案，但我对性能很好奇，今天2020.09.21我在Chrome+v85，Safariv13.1.2和Firefox+v80上对MacOs+HighSierra+10.13.6进行了测试，选择了解决方案。|5192249|结果|5192250|5192251|eval/Function+(A，B，C)方法在Chrome上速度很快(但对于大深度对象调用，它们会崩溃：“最大堆栈调用exceed)|unordered-list-item|offset|length|style|CODE|5192252|eval+(A)在所有browsers|5192253|JSON.parse+(D，E)上都是快/中快的在Safari和Firefox|5192254|+N=1000上是最快的|5192255|​|5192256|📷|atomic|5192257|5192258|详细信息|5192259|我执行4个测试用例：|5192260|小浅对象HERE|5192261|for小深对象HERE|5192262|
|5192263|for大浅对象HERE|5192264|5192265|for大深对象HERE|5192266|
的|5192267|5192268|5192269|上述测试中使用的对象来自HERE|5192270|5192271|let+obj_ShallowSmall+=+{
++field0:+false,
++field1:+true,
++field2:+1,
++field3:+0,
++field4:+null,
++field5:+[],
++field6:+{},
++field7:+"text7",
++field8:+"text8",
}

let+obj_DeepSmall+=+{
++level0:+{
+++level1:+{
++++level2:+{
+++++level3:+{
++++++level4:+{
+++++++level5:+{
++++++++level6:+{
+++++++++level7:+{
++++++++++level8:+{
+++++++++++level9:+[[[[[[[[[['abc']]]]]]]]]],
++}}}}}}}}},
};

let+obj_ShallowBig+=+Array(1000).fill(0).reduce((a,c,i)+=>+(a['field'%2Bi]=getField(i),a)+,{});


let+obj_DeepBig+=+genDeepObject(1000);



//+------------------
//+Show+objects
//+------------------

console.log('obj_ShallowSmall:',JSON.stringify(obj_ShallowSmall));
console.log('obj_DeepSmall:',JSON.stringify(obj_DeepSmall));
console.log('obj_ShallowBig:',JSON.stringify(obj_ShallowBig));
console.log('obj_DeepBig:',JSON.stringify(obj_DeepBig));




//+------------------
//+HELPERS
//+------------------

function+getField(k)+{
++let+i=k%2510;
++if(i==0)+return+false;
++if(i==1)+return+true;
++if(i==2)+return+k;
++if(i==3)+return+0;
++if(i==4)+return+null;
++if(i==5)+return+[];
++if(i==6)+return+{};++
++if(i>=7)+return+"text"%2Bk;
}

function+genDeepObject(N)+{
++//+generate:+{level0:{level1:{...levelN:+{end:[[[...N-times...['abc']...]]]+}}}...}}}
++let+obj={};
++let+o=obj;
++let+arr+=+[];
++let+a=arr;

++for(let+i=0;+i<N;+i%2B%2B)+{
++++o['level'%2Bi]={};
++++o=o['level'%2Bi];
++++let+aa=[];
++++a.push(aa);
++++a=aa;
++}

++a[0]='abc';
++o['end']=arr;
++return+obj;
}|code-block|syntax|javascript|5192272|5192273|下面的代码片段展示了所选的解决方案|5192274|5192275|//+src:+https://stackoverflow.com/q/45015/860099
function+A(json)+{
++return+eval("("+%2B+json+%2B+')');
}

//+https://stackoverflow.com/a/26377600/860099
function+B(json)+{
++return+(new+Function('return+('%2Bjson%2B')'))()
}


//+improved+https://stackoverflow.com/a/26377600/860099
function+C(json)+{
++return+Function('return+('%2Bjson%2B')')()
}

//+src:+https://stackoverflow.com/a/5686237/860099
function+D(json)+{
++return+JSON.parse(json);
}

//+src:+https://stackoverflow.com/a/233630/860099
function+E(json)+{
++return+$.parseJSON(json)
}



+
//+--------------------
//+TEST
//+--------------------

let+json+=+'{"a":"abc","b":"123","d":[1,2,3],"e":{"a":1,"b":2,"c":3}}';

[A,B,C,D,E].map(f=>+{++
++console.log(
++++f.name+%2B+'+'+%2B+JSON.stringify(f(json))
++)})|5192276|<script+src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
This+shippet+only+presents+functions+used+in+performance+tests+-+it+not+perform+tests+itself!|5192277|5192278|下面是chrome的示例结果|5192279|5192280|5192281|5192282|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/50e84f82e58cf98c1e2091de16b0e9cf.png|imageAlt|1|LINK|MUTABLE|url|https://jsbench.me/ipkf9kvabu/1|2|https://jsbench.me/57kf9ldcel/1|3|https://jsbench.me/5lkf9l9slg/1|4|https://jsbench.me/s6kf9lghxa/1|5|https://stackoverflow.com/a/61523278/860099|6|https://ask.qcloudimg.com/http-save/yehe-900000/927e6f753e604acba7a89ee4104c8f64.png^0|0|0|0|0|0|D|0|0|4|0|0|A|0|0|0|0|1|0|0|0|0|0|4|4|1|0|7|4|2|0|0|7|4|3|0|0|7|4|4|0|0|0|0|C|4|5|0|0|0|0|0|0|0|0|0|0|0|0|1|6|0|0^^$0|@$1|2|3|4|5|6|7|2S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|2T|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|2U|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|2V|8|@]|9|@]|A|$]]|$1|G|3|H|5|I|7|2W|8|@$J|2X|K|2Y|L|M]]|9|@]|A|$]]|$1|N|3|O|5|I|7|2Z|8|@$J|30|K|31|L|M]]|9|@]|A|$]]|$1|P|3|Q|5|I|7|32|8|@$J|33|K|34|L|M]]|9|@]|A|$]]|$1|R|3|S|5|6|7|35|8|@]|9|@]|A|$]]|$1|T|3|U|5|6|7|36|8|@]|9|@]|A|$]]|$1|V|3|W|5|X|7|37|8|@]|9|@$J|38|K|39|1|3A]]|A|$]]|$1|Y|3|U|5|6|7|3B|8|@]|9|@]|A|$]]|$1|Z|3|10|5|6|7|3C|8|@]|9|@]|A|$]]|$1|11|3|12|5|6|7|3D|8|@]|9|@]|A|$]]|$1|13|3|14|5|6|7|3E|8|@]|9|@$J|3F|K|3G|1|3H]]|A|$]]|$1|15|3|16|5|I|7|3I|8|@]|9|@$J|3J|K|3K|1|3L]]|A|$]]|$1|17|3|18|5|6|7|3M|8|@]|9|@]|A|$]]|$1|19|3|1A|5|I|7|3N|8|@]|9|@$J|3O|K|3P|1|3Q]]|A|$]]|$1|1B|3|18|5|6|7|3R|8|@]|9|@]|A|$]]|$1|1C|3|1D|5|I|7|3S|8|@]|9|@$J|3T|K|3U|1|3V]]|A|$]]|$1|1E|3|1F|5|6|7|3W|8|@]|9|@]|A|$]]|$1|1G|3|-4|5|I|7|3X|8|@]|9|@]|A|$]]|$1|1H|3|-4|5|6|7|3Y|8|@]|9|@]|A|$]]|$1|1I|3|1J|5|6|7|3Z|8|@]|9|@$J|40|K|41|1|42]]|A|$]]|$1|1K|3|U|5|6|7|43|8|@]|9|@]|A|$]]|$1|1L|3|1M|5|1N|7|44|8|@]|9|@]|A|$1O|1P]]|$1|1Q|3|U|5|6|7|45|8|@]|9|@]|A|$]]|$1|1R|3|1S|5|6|7|46|8|@]|9|@]|A|$]]|$1|1T|3|U|5|6|7|47|8|@]|9|@]|A|$]]|$1|1U|3|1V|5|1N|7|48|8|@]|9|@]|A|$1O|1P]]|$1|1W|3|1X|5|1N|7|49|8|@]|9|@]|A|$1O|1P]]|$1|1Y|3|U|5|6|7|4A|8|@]|9|@]|A|$]]|$1|1Z|3|20|5|6|7|4B|8|@]|9|@]|A|$]]|$1|21|3|U|5|6|7|4C|8|@]|9|@]|A|$]]|$1|22|3|W|5|X|7|4D|8|@]|9|@$J|4E|K|4F|1|4G]]|A|$]]|$1|23|3|U|5|6|7|4H|8|@]|9|@]|A|$]]|$1|24|3|-4|5|6|7|4I|8|@]|9|@]|A|$]]]|25|$26|$5|27|28|29|A|$2A|2B|2C|-4]]|2D|$5|2E|28|2F|A|$2G|2H]]|2I|$5|2E|28|2F|A|$2G|2J]]|2K|$5|2E|28|2F|A|$2G|2L]]|2M|$5|2E|28|2F|A|$2G|2N]]|2O|$5|2E|28|2F|A|$2G|2P]]|2Q|$5|27|28|29|A|$2A|2R|2C|-4]]]]

<h1>Performance</h1>
There are already good answer for this question, but I was curious about performance and today 2020.09.21 I conduct tests on MacOs HighSierra 10.13.6 on Chrome v85, Safari v13.1.2 and Firefox v80 for chosen solutions.
<h2>Results</h2>
<ul>
<li><code>eval/Function</code> (A,B,C) approach is fast on Chrome (but for big-deep object N=1000 they crash: &quot;maximum stack call exceed)</li>
<li><code>eval</code> (A) is fast/medium fast on all browsers</li>
<li><code>JSON.parse</code> (D,E) are fastest on Safari and Firefox</li>
</ul>
<a href="https://i.stack.imgur.com/Wzn1w.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Wzn1w.png" alt="enter image description here" /></a>
<h2>Details</h2>
I perform 4 tests cases:
<ul>
<li>for small shallow object <a href="https://jsbench.me/ipkf9kvabu/1" rel="nofollow noreferrer">HERE</a></li>
<li>for small deep object <a href="https://jsbench.me/57kf9ldcel/1" rel="nofollow noreferrer">HERE</a></li>
<li>for big shallow object <a href="https://jsbench.me/5lkf9l9slg/1" rel="nofollow noreferrer">HERE</a></li>
<li>for big deep object <a href="https://jsbench.me/s6kf9lghxa/1" rel="nofollow noreferrer">HERE</a></li>
</ul>
Object used in above tests came from <a href="https://stackoverflow.com/a/61523278/860099">HERE</a>
<div class="snippet" data-lang="js" data-hide="true" data-console="true" data-babel="false">
<div class="snippet-code snippet-currently-hidden">
<pre class="snippet-code-js lang-js prettyprint-override"><code>let obj_ShallowSmall = {
 field0: false,
 field1: true,
 field2: 1,
 field3: 0,
 field4: null,
 field5: [],
 field6: {},
 field7: "text7",
 field8: "text8",
}

let obj_DeepSmall = {
 level0: {
 level1: {
 level2: {
 level3: {
 level4: {
 level5: {
 level6: {
 level7: {
 level8: {
 level9: [[[[[[[[[['abc']]]]]]]]]],
 }}}}}}}}},
};

let obj_ShallowBig = Array(1000).fill(0).reduce((a,c,i) =&gt; (a['field'+i]=getField(i),a) ,{});


let obj_DeepBig = genDeepObject(1000);



// ------------------
// Show objects
// ------------------

console.log('obj_ShallowSmall:',JSON.stringify(obj_ShallowSmall));
console.log('obj_DeepSmall:',JSON.stringify(obj_DeepSmall));
console.log('obj_ShallowBig:',JSON.stringify(obj_ShallowBig));
console.log('obj_DeepBig:',JSON.stringify(obj_DeepBig));




// ------------------
// HELPERS
// ------------------

function getField(k) {
 let i=k%10;
 if(i==0) return false;
 if(i==1) return true;
 if(i==2) return k;
 if(i==3) return 0;
 if(i==4) return null;
 if(i==5) return [];
 if(i==6) return {}; 
 if(i&gt;=7) return "text"+k;
}

function genDeepObject(N) {
 // generate: {level0:{level1:{...levelN: {end:[[[...N-times...['abc']...]]] }}}...}}}
 let obj={};
 let o=obj;
 let arr = [];
 let a=arr;

 for(let i=0; i&lt;N; i++) {
 o['level'+i]={};
 o=o['level'+i];
 let aa=[];
 a.push(aa);
 a=aa;
 }

 a[0]='abc';
 o['end']=arr;
 return obj;
}</code></pre>
</div>
</div>

Below snippet presents chosen solutions
<div class="snippet" data-lang="js" data-hide="true" data-console="true" data-babel="false">
<div class="snippet-code snippet-currently-hidden">
<pre class="snippet-code-js lang-js prettyprint-override"><code>// src: https://stackoverflow.com/q/45015/860099
function A(json) {
 return eval("(" + json + ')');
}

// https://stackoverflow.com/a/26377600/860099
function B(json) {
 return (new Function('return ('+json+')'))()
}


// improved https://stackoverflow.com/a/26377600/860099
function C(json) {
 return Function('return ('+json+')')()
}

// src: https://stackoverflow.com/a/5686237/860099
function D(json) {
 return JSON.parse(json);
}

// src: https://stackoverflow.com/a/233630/860099
function E(json) {
 return $.parseJSON(json)
}



 
// --------------------
// TEST
// --------------------

let json = '{"a":"abc","b":"123","d":[1,2,3],"e":{"a":1,"b":2,"c":3}}';

[A,B,C,D,E].map(f=&gt; { 
 console.log(
 f.name + ' ' + JSON.stringify(f(json))
 )})</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"&gt;&lt;/script&gt;
This shippet only presents functions used in performance tests - it not perform tests itself!</code></pre>
</div>
</div>

And here are example results for chrome
<a href="https://i.stack.imgur.com/mzfaY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/mzfaY.png" alt="enter image description here" /></a>

blocks|key|5191723|text|试试this.This+one是用typescript写的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5191724|+++++++++export+function+safeJsonParse(str:+string)+{
+++++++++++++++try+{
+++++++++++++++++return+JSON.parse(str);
+++++++++++++++++++}+catch+(e)+{
+++++++++++++++++return+str;
+++++++++++++++++}
+++++++++++}|code-block|syntax|javascript|5191725|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try this.This one is written in typescript.

<pre><code> export function safeJsonParse(str: string) {
 try {
 return JSON.parse(str);
 } catch (e) {
 return str;
 }
 }
</code></pre>

blocks|key|2936244|text|/**
+*+Safely+turning+a+JSON+string+into+an+object
+*
+*+@param+{String}+str+-+JSON+String
+*+@returns+deserialized+object,+false+if+error
+*/
export+function+jsonParse(str)+{
++let+data+=+null;
++try+{
++++data+=+JSON.parse(str);
++}+catch+(err)+{
++++return+false;
++}
++return+data;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|2936245|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre class="lang-js prettyprint-override"><code>/**
 * Safely turning a JSON string into an object
 *
 * @param {String} str - JSON String
 * @returns deserialized object, false if error
 */
export function jsonParse(str) {
 let data = null;
 try {
 data = JSON.parse(str);
 } catch (err) {
 return false;
 }
 return data;
}
</code></pre>

Given a string of JSON data, how can I safely turn that string into a JavaScript object?

Obviously I can do this unsafely with something like:

<pre><code>var obj = eval("(" + json + ')');
</code></pre>

but that leaves me vulnerable to the JSON string containing other code, which it seems very dangerous to simply eval.

Safely turning a JSON string into an object

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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给定一个JSON数据字符串，如何安全地将该字符串转换为JavaScript对象？显然，我可以使用以下内容来不安全地执行此操作：var obj = eval("(" + json + ')');但这使我很容易受到包含其他代码的JSON字符串的影响，简单地对其求值似乎非常危险。

问安全地将JSON字符串转换为对象
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回答 26

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