Events

Both JSONDB and Collection extend Node’s EventEmitter. You can listen for useful lifecycle events to log activity, trigger side effects, or react to errors.

Listening

const db = new JSONDB('./data');
const users = db.collection({ name: 'users', autoId: true });

// Database-level listeners (receive events from every collection)
db.on('error', (err) => {
  console.error('[DB]', err.message);
});

db.on('insert', (info) => {
  console.log('Insert into', info.collection, info.document || info.count);
});

// Collection-level listeners
users.on('save', (info) => {
  console.log('Collection saved:', info.collection);
});

Event reference

Event	Emitted by	Payload	When
`error`	db & collection	`Error`	Any internal error (parse failure, write failure, …)
`insert`	db & collection	`{ collection, document }` or `{ collection, count }`	After a successful insert / insertMany
`update`	db & collection	`{ collection, count }`	After a successful update
`delete`	db & collection	`{ collection, count }`	After a successful delete
`save`	db & collection	`{ collection }`	After any write that persisted data
`import`	db & collection	`{ collection, count }`	After a successful import
`backup`	db	`{ path, pack }`	After a successful backup
`unload`	db	`{ collection }`	After `unloadCollection`
`index-rebuilt`	db & collection	`{ collection }`	After `rebuildIndexes`
`transactionCommit`	db & collection	`{ collection }`	After a transaction commits
`transactionRollback`	db & collection	`{ collection }`	After a transaction rolls back

Practical patterns

// Audit log of every change
db.on('insert', (info) => audit('insert', info));
db.on('update', (info) => audit('update', info));
db.on('delete', (info) => audit('delete', info));

// Central error reporting
db.on('error', (err) => {
  logger.error(err);
  // optionally notify a monitoring service
});

// React to index rebuilds
users.on('index-rebuilt', () => {
  console.log('Indexes are fresh again');
});