lowdb

import { JSONFilePreset } from 'lowdb/node'; import { fileURLToPath } from 'node:url'; import { dirname, join } from 'node:path'; // Resolve __dirname equivalent in ESM const __filename = fileURLToPath(import.meta.url); const __dirname = dirname(__filename); const dbFilePath = join(__dirname, 'db.json'); type Post = { id: number; title: string; views: number }; type Data = { posts: Post[] }; async function runDbExample() { // Define default data with type safety const defaultData: Data = { posts: [] }; // Initialize the database with a JSON file adapter // This will create 'db.json' if it doesn't exist, populated with defaultData const db = await JSONFilePreset<Data>(dbFilePath, defaultData); // Read the current data from the file await db.read(); console.log('Initial data:', db.data); // Add a new post using db.update() for atomic writes and automatic saving const newPost = { id: 1, title: 'lowdb is awesome', views: 100 }; await db.update(({ posts }) => posts.push(newPost)); console.log('Data after adding post:', db.data); // Query data using native JavaScript array methods const { posts } = db.data; const firstPost = posts.at(0); console.log('First post:', firstPost); // Modify an existing item and explicitly save if (firstPost) { firstPost.views += 10; // Modify in memory console.log('Modified post in memory:', firstPost); await db.write(); // Explicitly write changes back to db.json } console.log('Final data after explicit write:', db.data); } runDbExample().catch(console.error);