javascript 与 JSON.stringify() 相比，使用 toString() 有什么区别？
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What's the difference in using toString() compared to JSON.stringify()?
提问by user1883212
In both the cases I get in output the content of the object:
在这两种情况下，我都会输出对象的内容：
alert(JSON.stringify(obj));
or
或者
alert(obj.toString());
so... what's the difference? what are the advantages or disadvantages of each one?
所以……有什么区别？每一种的优点或缺点是什么？
Are there practical examples to show the difference?
是否有实际例子来说明差异？
回答by Esailija
Unless you have a custom object with custom .toStringmethod returning JSON.stringifyof that object, there is no objthat would give obj.toString() == JSON.stringify(obj).
除非您有一个带有自定义.toString方法返回JSON.stringify该对象的自定义对象，否则obj不会给obj.toString() == JSON.stringify(obj).
When objis an array like [1,2,3]then .toString()gives:
什么时候obj像[1,2,3]then这样的数组.toString()给出：
"1,2,3"
And JSON.stringify:
并且JSON.stringify：
"[1,2,3]"
These are close but not quite the same, the JSON serialized one has no ambiguity with commas and directly runs as Javascript or can be parsed as JSON.
这些很接近但不完全相同，JSON序列化的没有逗号歧义，直接作为Javascript运行或可以解析为JSON。
See:
看：
["1,",2,3].toString();
//"1,,2,3" ... so you can't just split by comma and get original array
//it is in fact impossible to restore the original array from this result
JSON.stringify(["1,",2,3])
//'["1,",2,3]'
//original array can be restored exactly
回答by Jacob George
for an object say
对于一个对象说
obj = { a: 'a', '1': 1 }
obj.toString()gives
obj.toString()给
"[object Object]"
JSON.stringify(obj)gives
JSON.stringify(obj)给
"{"1":1,"a":"a"}"
For .toString(), a default value is returned when the argument type is an object. JSON.stringifyon the other hand returns JSON text, which can be converted back into a JSON object by using JSON.parse
对于.toString()，当参数类型是对象时返回默认值。另一方面，JSON.stringify返回 JSON 文本，可以使用JSON.parse将其转换回 JSON 对象
回答by jAndy
As you might have noticed, while you tried (hopefully), calling .toString()which anyobject inherits (*)from Object.prototype.toString(), returns [object Object].
正如你可能已经注意到，当你尝试（希望），要求.toString()其任何对象继承（*）的Object.prototype.toString()，退货[object Object]。
Thats how its defined internally, returning the internal [Class]name from an object. Of course, other objectscan override this method (remember, its just originally defined on the prototype chain) and return pretty much anything.
这就是它在内部定义的方式，[Class]从对象返回内部名称。当然，其他对象可以覆盖这个方法（记住，它最初只是在原型链上定义的）并返回几乎任何东西。
JSON.stringify()on the other hand, is a method of the JSON object, which kind of serializesan object structure into a string version. Hence, Javascript Object Notation, it will describe an object with all nested structures in pure ascii string.
JSON.stringify()另一方面，是 JSON 对象的一种方法，将对象结构序列化为字符串版本。因此，Javascript Object Notation，它将用纯ascii string描述具有所有嵌套结构的对象。
(*) exception: objects created with Object.create(null);
(*) 异常：创建的对象 Object.create(null);
回答by Nayan Patel
You can use the replacer and space parameter in JSON.stringify, passing the replacer argument as a function you can modify the object and space parameter helps you to give extra space before every key value pair.
您可以在 JSON.stringify 中使用 replacer 和 space 参数，将 replacer 参数作为函数传递，您可以修改 object 和 space 参数帮助您在每个键值对之前留出额外的空间。
const replacer = (key, value) => {
// Filtering out properties
if (typeof value === 'number') {
return 1;
}
return value;
},
foo = {
country: 'India',
state: 'Gujarat',
district: 45,
cm: 'car',
am: 7
},
result = JSON.stringify(foo, replacer);
console.log(result) // {"country":"India","state":"Gujarat","district":1,"cm":"car","am":1}
Space argument -
空间论证——
const obj = { a : 1, b:2};
const obj_str = JSON.stringify(obj, null, ' ');// '\t' gives one tab
console.log(obj_str)
For more details you can visit this link.
有关更多详细信息，您可以访问此链接。
