T18: JSON Database

Before learning a real database, you can use a JSON file as a simple data store. Read the file, parse it, modify the data, and write it back. It is like a notebook where you write down and cross out entries - simple but effective for small applications.

Reading and Writing db.json

const fs = require("fs");
const DB_PATH = "./db.json";

function readDB() {
    const raw = fs.readFileSync(DB_PATH, "utf-8");
    return JSON.parse(raw);
}

function writeDB(data) {
    fs.writeFileSync(DB_PATH, JSON.stringify(data, null, 2));
}

CRUD Operations

// Create
function addUser(user) {
    const db = readDB();
    user.id = Date.now();
    db.users.push(user);
    writeDB(db);
    return user;
}

// Read
function getUsers() { return readDB().users; }

// Update
function updateUser(id, updates) {
    const db = readDB();
    const index = db.users.findIndex(u => u.id === id);
    if (index === -1) return null;
    db.users[index] = { ...db.users[index], ...updates };
    writeDB(db);
    return db.users[index];
}

// Delete
function deleteUser(id) {
    const db = readDB();
    db.users = db.users.filter(u => u.id !== id);
    writeDB(db);
}