CODEWITHSUNDEEP
javascriptnode.js
johnnasx
johnnasx

Reputation: 168

Create new object if it doesn't exist, else update

I'm having quite some trouble handling objects and storing them as JSON.

What I'm trying to do is next:

  1. parse json file
var links = JSON.parse([{"user1":{"username":"user1","data":"164"}},{"user2":{"username":"user2","status":0}}]);
  1. If user1 exists, update the whole object with new data, ELSE create new object
  var key     =  dater['username']; //dynamic username strings

  var ACCOUNT =  {
                    username: key,
                    data: value, 
                    status:1
                }

if(links.hasOwnProperty(key)){

   links[key] = ACCOUNT;
   links=JSON.stringify(links);

   fs.writeFile('status.json', links, err => {
       // error checking
       if(err) throw err;

       console.log('Exists.. updating.');
   });
}else{  // ELSE create new entry

       links.push({[key]: ACCOUNT});
       newData= JSON.stringify(links);

       fs.writeFile('status.json', newData, err => {
           // error checking
            if(err) throw err;

             console.log('New user.. creating');
       });

}

As you can probably tell, the above doesn't work as I'd want it to. I'm used with PHP arrays where I would simply do arrays with keys and directly update them without any 'if/else'

Upvotes: 0

Views: 1263

Answers (2)

Ron B.
Ron B.

Reputation: 1540

First of all, your usage of JSON.parse is incorrect, because the purpose of it is to take a string in JSON format and parse it to a JS object (or any other entity encoded in it). Your passing to it an array, and because JS has very expected and intuitive behavior, it tries to convert it to a string which end up being [Object object], which should result an error.

I assume it's just a typo and you forgot the "" before and after the array.

Second, links is an array. When you're using hasOwnProperty on this array, you're asking whether the array itself has this key, and not whether one of its members has.

There are 2 options:

Either

You can loop over the array with the some function and check whether one of the objects in the array has this key like so:

const isUserAlreadyExists = links.some(userObj => userObj.hasOwnProperty(key))

And use this as your condition

Or

Remodel your data so it's an object with the user names as keys, something like:

{
   user1: {username: "user1", data: whatever},
   user2: {username: "user2", data: whatever}
   ...
}

And then your current solution should work. I would suggest the second solution since your data model seems a bit weird, maybe consider different data structure altogether.

To do that, your initial data will have to be an empty object (const links = {} or wherever you're getting it from)

And then you can just keep the part in your if clause and it should work

So your code should be something like:

  var key     =  dater['username']; //dynamic username strings

  var ACCOUNT =  {
                    username: key,
                    data: value, 
                    status:1
                }

   links[key] = ACCOUNT;
   links=JSON.stringify(links);

   fs.writeFile('status.json', links, err => {
       // error checking
       if(err) throw err;

       console.log('Exists.. updating.');
   });

This way you don't have to check if the key property exists in your object, because if it doesn't it will simply create it and if it does it will overwrite whatever's stored in there

Upvotes: 1

CyberEternal
CyberEternal

Reputation: 2545

const key = dater['username']; //dynamic username strings

const account = {
    username: key,
    data: value,
    status: 1,
};

const matchedItem = links.find((i) => i[key]);

if (matchedItem) {
    matchedItem[key] = account;
} else {
    links.push({ [key]: account });
}

console.log('links:::', links);

fs.writeFile('status.json', JSON.stringify(links), (err) => {
    if (err) throw err;

    console.log('New user.. creating');
});

Upvotes: 1

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