joplin backup script like backup plugin with max backup count andonly backup when changes

joplin-backup.js

const { execSync } = require('child_process');
const fs = require('fs');

const backupDir = __dirname + '/joplin-backups'
const backupCount = 20
fs.mkdirSync(backupDir, { recursive: true })
const joplinSyncDir = 'C:/Users/admin/我的坚果云/webdav/Joplin'


let lastUpdatedAt = 0
const lastUpdatedAtFile = backupDir + '/lastUpdatedAt.txt'
if (fs.existsSync(lastUpdatedAtFile)) {
    lastUpdatedAt = parseFloat(fs.readFileSync(lastUpdatedAtFile, 'utf8'))
}


const files = fs.readdirSync(joplinSyncDir)

let curUpdatedAt = 0
for (const f of files) {
    const stat = fs.statSync(joplinSyncDir + '/' + f)
    if (stat.mtimeMs > curUpdatedAt) {
        curUpdatedAt = stat.mtimeMs
    }
}

fs.writeFileSync(lastUpdatedAtFile, curUpdatedAt.toString())

if (curUpdatedAt <= lastUpdatedAt) {
    console.log('no update')
    process.exit(0)
} else {
    const dir = backupDir
    console.log(execSync(`joplin sync`).toString())
    console.log(execSync(`joplin export --format=jex ${dir}/${new Date().toLocaleString().replace(/\W+/g, '-') + '.jex'}`).toString())
    const backupFiles = fs.readdirSync(dir)
    const backups = []
    for (const f of backupFiles) {
        if (!f.endsWith('.jex')) continue
        const stat = fs.statSync(dir + '/' + f)
        backups.push({
            file: f,
            mtime: stat.mtimeMs,
        })
    }
    backups.sort((a, b) => b.mtime - a.mtime)
    for (let i = backupCount; i < backups.length; i++) {
        fs.unlinkSync(dir + '/' + backups[i].file)
        console.log('delete backup', backups[i].file)
    }
}