mongo2mongo

library0.40.0jsnpmunverified

Sync one MongoDB collection to another MongoDB collection, supporting change streams and initial scans. Current stable version is 0.40.0, with regular releases. Requires Node >=16, peer dependencies include ioredis and mongodb (>=6.8.0). Key differentiators: built-in support for field omission, event-driven progress tracking, and batched initial sync with configurable batch sizes. Ships TypeScript types.

database devops

npm install mongo2mongo

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · MONGO2MONGO

mongo2mongo

databasejavascriptv0.40.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

initSync

✓ import { initSync } from 'mongo2mongo'

✗ const initSync = require('mongo2mongo')

ESM-only; CommonJS require is not supported.

Sync

✓ import type { Sync } from 'mongo2mongo'

✗ import { Sync } from 'mongo2mongo'

Sync is a TypeScript type, not a runtime export.

SyncOptions

✓ import type { SyncOptions } from 'mongo2mongo'

✗ import { SyncOptions } from 'mongo2mongo'

SyncOptions is a TypeScript type for configuration.

Initialize sync between two MongoDB collections with Redis, listen to events, start change stream and initial scan.

import { initSync } from 'mongo2mongo'; import Redis from 'ioredis'; import { MongoClient } from 'mongodb'; const client = await MongoClient.connect(process.env.MONGO_URI ?? ''); const db = client.db(); const sync = initSync( new Redis(process.env.REDIS_URL ?? ''), db.collection('source'), db.collection('destination'), { omit: ['password'] } ); sync.emitter.on('process', console.info); sync.emitter.on('error', console.error); const changeStream = await sync.processChangeStream(); changeStream.start(); const initialScan = await sync.runInitialScan({ batchSize: 1000 }); initialScan.start();

Debug

Known issues

breakingVersion 0.40.0 requires mongodb >=6.8.0 and ioredis >=5.4.1; older driver versions cause runtime errors.

fix

Update mongodb to >=6.8.0 and ioredis to >=5.4.1.

affects: >=0.40.0

breakingNode.js version must be >=16.0.0; older versions are not supported.

fix

Upgrade Node.js to 16 or later.

affects: >=0.40.0

gotchaThe sync object's emitter property must be accessed before calling processChangeStream or runInitialScan to avoid missing events.

fix

Attach event listeners immediately after initSync.

affects: >=0.0.0

deprecatedThe 'omit' option accepts an array of field names to exclude from sync; this may be deprecated in future versions.

fix

Check future releases for alternative API.

affects: >=0.30.0

gotchaIf source and destination databases are different, ensure both connections are provided correctly via MongoClient.

fix

Use separate MongoClient instances if needed, or connect to the same client with different databases.

affects: >=0.0.0

breakingThe package previously exported a default export; now only named export { initSync } is available.

fix

Change import to named import: import { initSync } from 'mongo2mongo'.

affects: >=0.40.0

Errors

Common errors & fixes

Cannot find module 'mongo2mongo'

Package not installed or ESM module resolution issue.

fix

Run npm install mongo2mongo or ensure package.json has 'type': 'module'.

initSync is not a function

Using default import or incorrect require syntax.

fix

Use named import: import { initSync } from 'mongo2mongo'.

The module 'ioredis' is not compatible with the 'mongodb' driver version

Peer dependency version mismatch.

fix

Install compatible versions: npm install ioredis@5.4.1 mongodb@6.8.0

TypeError: Cannot read properties of undefined (reading 'on')

Attempting to use sync.emitter before it's initialized or without calling initSync.

fix

Ensure you call initSync and use the returned sync object.

Upgrade

Version history

0.40.0latest on npm

Audit

Dependencies

ioredisrequiredUsed for managing change stream cursors and coordination

mongodbrequiredOfficial MongoDB driver for interacting with databases

Agent activity

10 hits · last 30 days

node

Resources

githubgit://github.com/smartprocure/mongo2mongo ↗

packagemongo2mongo ↗

homepagehttps://github.com/smartprocure/mongo2mongo#readme ↗