// cli.js
import { LowSync } from 'lowdb'
import { JSONFileSync } from 'lowdb/node'
const title = process.argv[2]
const adapter = new JSONFileSync('file.json')
const db = new LowSync(adapter)
db.read()
db.data ||= { posts: [] }
db.data.posts.push({ title })
db.write()$ node cli.js "hello world"
$ cat file.json
# { "posts": [ "title": "hello world" ] }import { LowSync } from 'lowdb'
import { LocalStorage } from 'lowdb/browser'
const adapter = new LocalStorage('db')
const db = new LowSync(adapter)
db.read()
db.data ||= { posts: [] }
db.data.posts.push({ title: 'lowdb' })
db.write()Note if you're developing a local server and don't expect to get concurrent requests, it can be easier to use JSONFileSync adapter.
But if you need to avoid blocking requests, you can do so by using JSONFile adapter.
import express from 'express'
import { Low } from 'lowdb'
import { JSONFile } from 'lowdb/node'
const app = express()
app.use(express.json())
const adapter = new JSONFile('db.json')
const db = new Low(adapter)
await db.read()
db.data ||= { posts: [] }
const { posts } = db.data
app.get('/posts/:id', async (req, res) => {
const post = posts.find((p) => p.id === req.params.id)
res.send(post)
})
app.post('/posts', async (req, res, next) => {
const post = posts.push(req.body)
await db.write()
res.send(post)
})
app.listen(3000, () => {
console.log('listening on port 3000')
})With this adapter, calling db.write() will do nothing. One use case for this adapter can be for tests.
import { LowSync, MemorySync } from 'lowdb'
import { JSONFileSync } from 'lowdb/node'
const adapter =
process.env.NODE_ENV === 'test' ? new MemorySync() : new FileSync('db.json')
const db = new LowSync(adapter)Memory and MemorySync can also be found in lowdb/browser.