Convert JS object to JSON string

Question

If I defined an object in JS with:

var j={"name":"binchen"};

How can I convert the object to JSON? The output string should be:

'{"name":"binchen"}'

Solution 1

All current browsers have native JSON support built in. So as long as you're not dealing with prehistoric browsers like IE6/7 you can do it just as easily as that:

var j = {
  "name": "binchen"
};
console.log(JSON.stringify(j));

Solution 2

With JSON.stringify() found in json2.js or native in most modern browsers.

JSON.stringify(value, replacer, space)
    value       any JavaScript value, usually an object or array.
    replacer    an optional parameter that determines how object
                values are stringified for objects. It can be a
                function or an array of strings.
    space       an optional parameter that specifies the indentation
                of nested structures. If it is omitted, the text will
                be packed without extra whitespace. If it is a number,
                it will specify the number of spaces to indent at each
                level. If it is a string (such as "\t" or " "),
                it contains the characters used to indent at each level.

Solution 3

Check out updated/better way by Thomas Frank:

• JSON stringify revisited

Update May 17, 2008: Small sanitizer added to the toObject-method. Now toObject() will not eval() the string if it finds any malicious code in it.For even more security: Don't set the includeFunctions flag to true.

Douglas Crockford, father of the JSON concept, wrote one of the first stringifiers for JavaScript. Later Steve Yen at Trim Path wrote a nice improved version which I have used for some time. It's my changes to Steve's version that I'd like to share with you. Basically they stemmed from my wish to make the stringifier:

• handle and restore cyclical references
• include the JavaScript code for functions/methods (as an option)
• exclude object members from Object.prototype if needed.

Solution 4

You can use JSON.stringify() method to convert JSON object to String.

var j={"name":"binchen"};
JSON.stringify(j)

For reverse process, you can use JSON.parse() method to convert JSON String to JSON Object.

Solution 5

JSON.stringify(j, null, 4) would give you beautified JSON in case you need beautification also

The second parameter is replacer. It can be used as Filter where you can filter out certain key values when stringifying. If set to null it will return all key value pairs

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Comments

[Gowtham]

JSON.stringify() is the method you're looking for.

[Egan Wolf]

There's always that first time when you have to learn it.

[Justin Meskan]

JSON.stringify is also a good way to copy an object

[AabinGunz]

download this script in order for JSON.stringify(j); to work

[georgelviv]

Work on nodejs because node use same engine

[Andris]

This answer was posted a year before IE9 was released so at the time of writing IE8 was a modern browser indeed, or at least it was the newest IE available.

[alphakevin]

does not escape strings with quotation marks like: "a \" in a string"

[Glenn Lawrence]

For a bit more clarity: replacer is optional, so if you want to still use the space arg you put null for replacer. If you are interested in using this function for pretty printing I found this answer to be also useful: stackoverflow.com/a/7220510/857209

[David Lavieri]

Thanks for adding the reverse process.

[Ritesh]

JSON.stringify doesn't convert nested objects. Any solution for that..??

[Fanky]

to be precise j=JSON.stringify(j); or var newvar=JSON.stringify(j);

[Jacek Gzel]

If You need more readable json string You can use space parameter like var formattedJSON = JSON.stringify(j, null, 2);

[Manuel Romeiro]

That custom code is very incomplete. Does not support arrays, objects and special chars. Example: the json {"arr":["1", "2", "3"],"obj":{"a":"b"},"key\"with\\special}chars":"value"} will output {"arr":"1,2,3","obj":"[object Object]","key"with\special}chars":"value"} that is wrong!

[Mohammad Ghonchesefidi]

You just saved my day. I was not able to save my object. the key that fields which have undefined value will not be included into json solved my problem!

[yash]

References of JSON parsing in JS: JSON.parse() : w3schools.com/js/js_json_parse.asp JSON.stringify() : w3schools.com/js/js_json_stringify.asp

[Rohit Kumar]

ofcourse this code is just an example of playing with codes .. we should always use stringify ... JS had done the job already for us