Add data to existing json object

Question

So what i'm trying to achieve is creating a json flat file to store user info where i'm stuck is that i don't know how to add new nested objects that are empty and then save the json file and reload it.

what i have in my *json* file is this.

{
    "users" : {
        "test" : {

        },
        "test1" : {

        }
    }
}

I'm trying to add as many new objects as i want to it. So for example.

{
    "users" : {
        "test" : {

        },
        "test1" : {

        },
        "test2" : {

        },
        "test3" : {

        }
    }
}

My server side Javascript

    json.users.push = username;
    fs.writeFile("./storage.json", JSON.stringify(json, null, 4) , 'utf-8');
    delete require.cache[require.resolve('./storage.json')];
    json = require("./storage.json");

With this code it does not write the file so when the require is done i end up with the same file and my json object ends up like this when i console.log it

{                                                                                                                                                    
    "users": {                                                                                                                                       
        "test": {},                                                                                                                                  
        "test1": {},                                                                                                                                 
        "push": "test2"                                                                                                                                
    }                                                                                                                                                
}

Please do not recommend some external module to solve something has simple as this. Also if any one can point me to a in depth json documentation that gets straight to the point with what i'm try to do it would be appreciated

there is no such thing as JSON object. there's object, and there's JSON. it's the difference between a cake-recipe and a cake. there is no such thing cake-recipe-cake. — David Haim
– David Haim, Commented Oct 5, 2015 at 3:12

Mulan · Accepted Answer · 2015-10-05 03:10:28Z

3

Use [] to access a dynamic key on the object

json.users[username] = {a: 1, b: 2}

Be careful naming your variable like that tho because json the way you're using it is not JSON. JSON is a string, not an object with keys.

See the below demo for distinction

var json = '{"users":{"test1":{},"test2":{}}}';
var obj  = JSON.parse(json);
var newuser = 'test3';
obj.users[newuser] = {};
console.log(JSON.stringify(obj));
//=> {"users":{"test1":{},"test2":{},"test3":{}}}

answered Oct 5, 2015 at 3:10

Mulan

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5 Comments

Darkrum Over a year ago

Straight to the point! You're awesome! Do you know where i can find a in depth documentation on manipulating json with JavaScript also do you have any clue why my fs.writefile is not working?

Mulan Over a year ago

You never manipulate JSON directly. Always var x = JSON.parse(yourJson), perform manipulations on x, then JSON.stringify(x) to rewrite the JSON.

Darkrum Over a year ago

I understand that what i am doing is non standard and that i must watch myself carefully to not screw up.

Mulan Over a year ago

it looks like you're trying to use fs.writeFile in a synchronous way, maybe try fs.writeFileSync. If that doesn't help, you should ask a new question.

Darkrum Over a year ago

no i know that you use parse and stringify. i was not using manipulation in that sense.

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