jQuery 如何检查它是字符串还是json
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How to check if it's a string or json
提问by crzyonez777
I have a json string that is converted from object by JSON.Stringify function.
我有一个由 JSON.Stringify 函数从对象转换而来的 json 字符串。
I'd like to know if it's json string or just a regular string.
我想知道它是 json 字符串还是只是一个普通字符串。
Is there any function like "isJson()" to check if it's json or not?
有没有像“isJson()”这样的函数来检查它是否是json？
I'd like to use the function when I use local storage like the code below.
当我像下面的代码一样使用本地存储时，我想使用该功能。
Thank you in advance!!
先感谢您！！
var Storage = function(){}
Storage.prototype = {
setStorage: function(key, data){
if(typeof data == 'object'){
data = JSON.stringify(data);
localStorage.setItem(key, data);
} else {
localStorage.setItem(key, data);
}
},
getStorage: function(key){
var data = localStorage.getItem(key);
if(isJson(data){ // is there any function to check if the argument is json or string?
data = JSON.parse(data);
return data;
} else {
return data;
}
}
}
var storage = new Storage();
storage.setStorage('test', {x:'x', y:'y'});
console.log(storage.getStorage('test'));
回答by Niet the Dark Absol
The "easy" way is to tryparsing and return the unparsed string on failure:
“简单”的方法是try解析并在失败时返回未解析的字符串：
var data = localStorage[key];
try {return JSON.parse(data);}
catch(e) {return data;}
回答by letiagoalves
you can easily make one using JSON.parse. When it receives a not valid JSON string it throws an exception.
您可以轻松地使用JSON.parse. 当它收到无效的 JSON 字符串时，它会引发异常。
function isJSON(data) {
var ret = true;
try {
JSON.parse(data);
}catch(e) {
ret = false;
}
return ret;
}
回答by Benoit Gauthier
Found this in another post How do you know if an object is JSON in javascript?
在另一篇文章中找到了这个你如何知道一个对象是否是 javascript 中的 JSON？
function isJSON(data) {
var isJson = false
try {
// this works with JSON string and JSON object, not sure about others
var json = $.parseJSON(data);
isJson = typeof json === 'object' ;
} catch (ex) {
console.error('data is not JSON');
}
return isJson;
}
回答by darmis
Since the question is "How to check if it's a string or json" maybe a simple way would be to check for string, so you would have done something like this somewhere:
由于问题是“如何检查它是字符串还是 json”，因此检查字符串可能是一种简单的方法，因此您可以在某处执行以下操作：
if (typeof data === 'string') { // check for string!
//... do something
} else {///... do something else}
Maybe that could be enough depending on your overall solution, just in case someone else is looking around.
也许这可能就足够了，这取决于您的整体解决方案，以防其他人四处张望。
回答by Mehdi Dehghani
I think returning parsed JSON at the same time is a good idea, so I prefer following version:
我认为同时返回解析的 JSON 是个好主意，所以我更喜欢以下版本：
function tryParse(str) {
try {
return { value: JSON.parse(str), isValid: true }
} catch (e) {
return { value: str, isValid: false }
}
}
As you probably know JSON.parse("1234"), JSON.parse("0"), JSON.parse("false")and JSON.parse("null")won't raise Exception and will return true. all this values are valid JSON but if you want to see isValidis trueonly for objects (e.g: { "key": "value" }) and arrays (e.g: [{ "key": "value" }]) you can use following version:
正如你可能知道JSON.parse("1234")，JSON.parse("0")，JSON.parse("false")并JSON.parse("null")不会引发异常，将返回true。所有这些值是有效的JSON，但如果你希望看到的isValid是true只为对象（例如：{ "key": "value" }）和阵列（例如：[{ "key": "value" }]），可以使用以下版本：
function tryParse(str) {
try {
var parsed = JSON.parse(str);
return { value: parsed , isValid: typeof parsed === 'object'}
} catch (e) {
return { value: str, isValid: false }
}
}
