Writing and Reading JSON files in javascript

Question

So I am doing a project right now requiring the storage of user preferences with JSON. I have searched for a decent amount of time now but can find no solution.For example sake There are three variables user, permissions, serverid . I figured this would work.

tempObject = {
    user: []
};

tempObject.user.push({perm:permissions, server:serverid});

Then i would stringify and turn into a JSON. However the output came out like this:

{user[{perm:4, server:883}]}

This was my desperate attempt at grouping the perm and server variables under the indivisuals UserID so further down in the code i can fetch the permissions of each userID. But as you can see it didnt print the user variable, just changed it to an array and took user as a litteral string.

tl;dr In short i need help being able to have a JSON file be written to where it stores the perm and serverID under the UserID.

ILikeTacos · Accepted Answer · 2017-03-23 01:07:37Z

2

Make user an object. Change this:

user: []

for this:

user: {}

and then set the keys like this:

user.perm = 4;
user.server = 883;

answered Mar 23, 2017 at 1:07

ILikeTacos

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Rob Brander · Accepted Answer · 2017-03-23 01:14:50Z

For security reasons, client-side JavaScript is not permitted to write to the disk. This sounds like you need a database.

You could leverage localStorage, or perhaps a cookie as an alternate to a database.

I think you should change the users array to an object; that way could key by userID.

for example:

var data = {
  users: {}
};

const userID = 1234; // or could be a string like 'john_doe'
const userPermissions = { perm: 4, server: 883 };

// set the user's permissions
data.users[userID] = userPermissions;

// fetching user's permissions
const userData = data.users[userID];
console.log('User ' + userID +' has perm = ' + userData.perm + ' and server = ' + userData.server);

Now saving and loading of this data using local storage is easy:

function saveData() {
  localStorage.setItem('UserData', JSON.stringify(data));
}

function loadData() {
  data = JSON.parse(localStorage.getItem('UserData'));
}

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