Parsing a json tree in nodejs

Question

I need to parse a json placed in a file and identify its structure below is the code where I tried doing that

var fs = require('fs')
var reqTemplate;
var obj;
fs.readFile('SampleData.js', 'utf8', function (err, data) {
    if (err) {
        return console.log(err);
    }
    reqTemplate = data;
    console.log('\nRequestTemplate:\n\n%s\n', reqTemplate);
    obj = JSON.parse(reqTemplate);
    var i = 0;
    console.log(Object.keys(obj));
    Object.keys(obj).forEach(function (key) {
        i++;
        console.log;
        console.log(key);
        console.log(obj[key]);
    });
});

The output that I got is:

{
    "AuthenticateUserReq": {
        "Tid": "123",
        "username": "131329",
        "password": "Vinod",
        "SessionTokenId": "",
        "DeviceInfo": {
            "DeviceName": "ABC",
            "DeviceVersion": "X",
            "UniqueDeviceID": "ZZZ",
            "Platform": "AND"
        }
    }
}

I'm able to get the parent key and its values.
I'm stuck as how to identify the child key and retrieval of its values.

PS: I wont be aware of the structure of the json response. I need to identify the root key and its value and also the children key and their values.

Any help will be much appreciated.

Why do you need to iterate through the object manually? Isn't the object you want simply JSON.parse(reqTemplate)? — Cerbrus
– Cerbrus, Commented Dec 27, 2012 at 11:43
@Cerbrus:That is just giving me the entire response.I want to get the individual keys and their values. — Amanda G
– Amanda G, Commented Dec 27, 2012 at 12:43

Bergi · Accepted Answer · 2013-04-14 12:04:15Z

4

You will need recursion for tree traversal:

var callback = console.log;

function traverse(obj) {
    if (obj instanceof Array) {
        for (var i=0; i<obj.length; i++) {
            if (typeof obj[i] == "object" && obj[i]) {
                callback(i);
                traverse(obj[i]);
            } else {
                callback(i, obj[i])
            }
        }
    } else {
        for (var prop in obj) {
            if (typeof obj[prop] == "object" && obj[prop]) {
                callback(prop);
                traverse(obj[prop]);
            } else {
                callback(prop, obj[prop]);
            }
        }
    }
}

traverse( JSON.parse(reqTemplate) );

edited Apr 14, 2013 at 12:04

answered Dec 27, 2012 at 11:11

Bergi

671k162 gold badges1k silver badges1.5k bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Amanda G Over a year ago

:Thanks i tried your solution and was able to come up with the required output.

AlexGad · Accepted Answer · 2012-12-28 14:15:07Z

2

Might also want to try out Node traverse - https://github.com/substack/js-traverse. Allows recursively walking a JSON tree to get each key value pair with context (ie: keeps track of parent), and can run map/reduce while traversing tree. Very powerful.

answered Dec 28, 2012 at 14:15

AlexGad

6,7025 gold badges36 silver badges46 bronze badges

Comments

sqreept · Accepted Answer · 2012-12-27 11:24:41Z

0

When you parse a JSON you get a normal JS object. You can obtain its keys by using var keysOfObject = Object.keys(object);. Then you can use those keys to get the values.

answered Dec 27, 2012 at 11:24

sqreept

5,5743 gold badges23 silver badges26 bronze badges

3 Comments

Amanda G Over a year ago

yup when i tried dat i am able to get oly the parent key say AuthenticateUserReq from the above json.But i also want to get the DeviceInfo (ie)The main keys inside a parent key is not retrived in the above method

sqreept Over a year ago

But what's your purpose? Why do you want to traverse the JSON? Looking for something? Or you just want to print it out?

Amanda G Over a year ago

I want to traverse the JSON store its keys in a db and also i should be able to bring back the json in its original formal by retrieving its contents from the db

Collectives™ on Stack Overflow

Parsing a json tree in nodejs

3 Answers 3

1 Comment

Comments

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related