Troubleshooting

TypeScript: db.users does not exist / is any

Cause: schemas array not as const, or schemas not passed to createClient.

export const schemas = [userSchema] as const; // required
const connect = createClient({ serverless: true, schemas });

Use SchemasToClient<typeof schemas> for shared types.

ZodError on create

Common causes:

• Missing .required() field
• Invalid email/url/pattern
• Wrong type (string vs number)
• Enum value not in list

Inspect error.issues for path and message.

Defaults only apply when the field is missing and validation mode is not off.

Update rejected but $inc works

Only plain objects and $set / $setOnInsert are validated.
If $set: { age: -1 } fails min validation, that is expected in strict mode.

Indexes never appear

Indexes are not created automatically on connect (unless deprecated syncIndexes: true).

npx mondel push --uri "$MONGODB_URI" --schema ./dist/schemas.js --dry-run
npx mondel push --uri "$MONGODB_URI" --schema ./dist/schemas.js

Ensure the schema module is compiled JS and exports schemas.

push cannot load TypeScript config

Install typescript in the project, or use mondel.config.js / .mjs.

Connection storms on serverless

Connecting and never reusing clients under huge concurrency can hit Atlas limits.

• Lower maxPoolSize
• Reuse factory; avoid opening many clients per request without need
• Prefer platform guidance for Lambda freeze/reuse
• Always use Atlas SRV connection strings

Soft delete documents still show up

Soft delete only sets deletedAt. Filter them out in queries:

await db.users.findMany({ deletedAt: { $exists: false } });

Transactions fail on standalone MongoDB

Multi-document transactions need a replica set (Atlas provides this). Local single mongod without replSet will error.

ObjectId / BSON mismatch errors

Import ObjectId from mondel (or the same mongodb package version as the peer), not from a nested duplicate bson.

Geospatial queries return nothing

• Coordinates are [longitude, latitude]
• Index must be 2dsphere (run mondel push)
• MongoDB 8 rejects malformed geo input

select fields missing at runtime but TS allows access

Projection is runtime-only; TypeScript does not narrow. Only use projected fields, or omit select.

Still stuck?

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• GitHub Issues
• Compatibility