A Guide to Discord Bots

Storing Data Using JSON

A JSON editor, formatter and viewer.

Definition

JSON, JavaScript Object Notation, is a data formating which is lightweight and easy to use.
It became a standard in JavaScript.
When saving JSON data to a file, we can use *.json.

Here's an example:

// This works
var obj = {name:"John", age:20}; //property: value

// But here's a more readable formatting
obj = {
    name: "John",
    age: 20
}

Note: in JSON, name: 'John' is invalid while name: "John" is valid.

Adding elements

var obj = {}; // An empty object

obj.name = "John";
obj.age = 20;
obj.credentials = {}; // A nested object

// Using variables
let property = "username";
let value = "john12";
obj.credentials[property] = value;

// this will set obj.credentials.password to the correct value
// obj.credentials.property will not work!

Setting elements

var obj = {
    name: "John",
    age: 20,
    credentials: {
        username: "john12",
        password: "$2a$08$jT5j9kxru4/qUv4PItExa.sl579k0SvrqEU8SKniawfiitAC/6Ua2"
    }
}

obj.name = "David";
obj.credentials.password = "password"

obj.credentials = {username: "david12"};
// this will remove everything and set "username" to "david12"

// Using variables
let property = "password";
let value = "David";

obj.credentials[property] = value;
// this will set obj.credentials.password to the correct value
// obj.credentials.property will not work!

// Final result:
/* {
    name: "David",
    age: 20,
    credentials: {
        username: "david12",
        password: "$2a$08$yndOdxl7QgloOwTrHima/u0pf5/ZXq0N9mHlzqGLXg7UY4caZaZCS"
    }
} */

Getting elements

var obj = {
    name: "John",
    age: 20,
    credentials: {
        username: "john12",
        password: "$2a$08$jT5j9kxru4/qUv4PItExa.sl579k0SvrqEU8SKniawfiitAC/6Ua2"
    }
}

console.log('Name: ' + obj.name);
console.log('Age: ' + obj.age);
console.log('Credentials: ' + obj.credentials);
console.log('Username: ' + obj.credentials.username);
console.log('Object: ' + obj);
// You can output objects directly to the console

Checking if an element exists

var obj = {
    name: "John",
    age: 20,
    credentials: {
        username: "john12",
        password: "$2a$08$jT5j9kxru4/qUv4PItExa.sl579k0SvrqEU8SKniawfiitAC/6Ua2"
    }
}

if (obj.hasOwnProperty("name"))
    console.log('Name: ' + obj.name);

if (obj.hasOwnProperty("credentials"))
    if (obj.credentials.hasOwnProperty("username"))
        console.log('Username: ' + obj.credentials.username);

Removing elements

var obj = {
    name: "John",
    age: 20,
    credentials: {
        nickname: "John",
        username: "john12",
        password: "$2a$08$jT5j9kxru4/qUv4PItExa.sl579k0SvrqEU8SKniawfiitAC/6Ua2"
    }
}

delete obj.age;
delete obj.credentials.username;

// Using variables
let property = "password";
delete obj.credentials[property];

// Final result:
/* {
    name: "John",
    credentials: {
        nickname: "John"
    }

} */

Getting an object's size

var obj = {
    name: "John",
    age: 20
}

console.log('Length: ' + Object.keys(obj).length);
// Length: 2

obj = {
    name: "John",
    age: 20,
    credentials: {
        nickname: "John",
        username: "john12",
        password: "$2a$08$jT5j9kxru4/qUv4PItExa.sl579k0SvrqEU8SKniawfiitAC/6Ua2"
    }
}

console.log('Length: ' + Object.keys(obj).length);
// Length: 3
// Because Object.keys(obj) = [ 'name', 'age', 'credentials' ]

For loops

var obj = {
    name: "John",
    age: 20
};

for (let property in obj)
    console.log(`${property}: ${obj[property]}`);

// Output:
// name: John
// age: 20

Writing JSON to a file

const fs = require('fs');

var obj = {
    name: "John",
    age: 20
};

fs.writeFileSync('./data.json', JSON.stringify(obj));

Reading a JSON file

const fs = require('fs');

var obj = JSON.parse(fs.readFileSync('./data.json'));