Method

Description

parse(text, callback)

Takes a JSON-encoded string and returns an object:

    > var data = '{"hello":   1, "hi": [1, 2, 3]}';   
    > var o = JSON.parse(data);   
    > o.hello;   
    1   
    > o.hi;   
    [1, 2, 3]   

The optional callback lets you provide your own function that can inspect and modify the result. The callback takes key and value arguments and can modify the value or delete it (by returning undefined).

    > function callback(key, value)   {   
        console.log(key, value);   
        if (key === 'hello') {   
          return 'bonjour';   
        }   
        if (key === 'hi') {   
          return undefined;   
        }   
        return value;   
      }   
   
    > var o = JSON.parse(data, callback);   
    hello 1   
    0 1   
    1 2   
    2 3   
    hi [1, 2, 3]   
    Object {hello: "bonjour"}   
    > o.hello;   
    "bonjour"   
    > 'hi' in o;   
    false   

stringify(value, callback, white)

Takes any value (most commonly an object or an array) and encodes it to a JSON string.

    > var o = {   
    hello: 1,    
    hi: 2,    
    when: new Date(2015, 0, 1)   
   };   
   
    > JSON.stringify(o);   
   "{"hello":1,"hi":2,"when":
    "2015-01-01T08:00:00.000Z"}"   

The second parameter lets you provide a callback (or a whitelist array) to customize the return value. The whitelist contains the keys you're interested in:

    JSON.stringify(o, ['hello', 'hi']);   
    "{"hello":1,"hi":2}"   

The last parameter helps you get a human-readable version. You specify the number of spaces as a string or a number:

    > JSON.stringify(o, null, 4);   
    "{   
    "hello": 1,   
    "hi": 2,   
    "when": "2015-01-01T08:00:00.000Z"   
    }"